simdutf: simdutf_connector: in_tail: Implement UTF-16LE/UTF-16BE encoder

[cosmo0920]

In Windows, there are lots of using UTF-16LE programs. This is because Unicode on Windows means UTF-16LE with BOM(Byte Order Mark).
In addition, there is lots of differences between UTF-16LE/UTF-16BE and UTF-8.
I added some of C, J and subdivision flags test cases for converting from UTF-16LE/UTF-16BE to UTF-8 in unit tests for in_tail plugin. This is because in_tail is the main usages to process non-UTF-8 encodings.
At first, we need to process UTF-16LE and UTF-16BE encodings.

Note that simdutf library is written in C++. So, we also provide an option (FLB_UNICODE_ENCODER) to turn on/off this feature.

Closes #9321

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Testing
Before we can approve your change; please submit the following in a comment:

• Example configuration file for the change

[SERVICE]
   flush           1
   log_level       trace

[INPUT]
   Name              tail
   Path              <path/to/non-UTF-16_encoded_file.log>
   Read_from_Head    True
   Unicode.Encoding  auto

[OUTPUT]
   Name  stdout
   Match *

• Debug log output from testing the change

Fluent Bit v3.2.0
* Copyright (C) 2015-2024 The Fluent Bit Authors
* Fluent Bit is a CNCF sub-project under the umbrella of Fluentd
* https://fluentbit.io

______ _                  _    ______ _ _           _____  _____ 
|  ___| |                | |   | ___ (_) |         |____ |/ __  \
| |_  | |_   _  ___ _ __ | |_  | |_/ /_| |_  __   __   / /`' / /'
|  _| | | | | |/ _ \ '_ \| __| | ___ \ | __| \ \ / /   \ \  / /  
| |   | | |_| |  __/ | | | |_  | |_/ / | |_   \ V /.___/ /./ /___
\_|   |_|\__,_|\___|_| |_|\__| \____/|_|\__|   \_/ \____(_)_____/


[2024/10/07 16:01:31] [ info] Configuration:
[2024/10/07 16:01:31] [ info]  flush time     | 1.000000 seconds
[2024/10/07 16:01:31] [ info]  grace          | 5 seconds
[2024/10/07 16:01:31] [ info]  daemon         | 0
[2024/10/07 16:01:31] [ info] ___________
[2024/10/07 16:01:31] [ info]  inputs:
[2024/10/07 16:01:31] [ info]      tail
[2024/10/07 16:01:31] [ info] ___________
[2024/10/07 16:01:31] [ info]  filters:
[2024/10/07 16:01:31] [ info] ___________
[2024/10/07 16:01:31] [ info]  outputs:
[2024/10/07 16:01:31] [ info]      stdout.0
[2024/10/07 16:01:31] [ info] ___________
[2024/10/07 16:01:31] [ info]  collectors:
[2024/10/07 16:01:31] [ info] [fluent bit] version=3.2.0, commit=c9e98dac6a, pid=3617897
[2024/10/07 16:01:31] [debug] [engine] coroutine stack size: 24576 bytes (24.0K)
[2024/10/07 16:01:31] [ info] [storage] ver=1.1.6, type=memory, sync=normal, checksum=off, max_chunks_up=128
[2024/10/07 16:01:31] [ info] [cmetrics] version=0.9.6
[2024/10/07 16:01:31] [ info] [ctraces ] version=0.5.6
[2024/10/07 16:01:31] [ info] [input:tail:tail.0] initializing
[2024/10/07 16:01:31] [ info] [input:tail:tail.0] storage_strategy='memory' (memory only)
[2024/10/07 16:01:31] [debug] [tail:tail.0] created event channels: read=25 write=26
[2024/10/07 16:01:31] [debug] [input:tail:tail.0] flb_tail_fs_inotify_init() initializing inotify tail input
[2024/10/07 16:01:31] [debug] [input:tail:tail.0] inotify watch fd=31
[2024/10/07 16:01:31] [debug] [input:tail:tail.0] scanning path unicode_c.log
[2024/10/07 16:01:31] [debug] [input:tail:tail.0] file will be read in POSIX_FADV_DONTNEED mode unicode_c.log
[2024/10/07 16:01:31] [debug] [input:tail:tail.0] inode=42736996 with offset=0 appended as unicode_c.log
[2024/10/07 16:01:31] [debug] [input:tail:tail.0] scan_glob add(): unicode_c.log, inode 42736996
[2024/10/07 16:01:31] [debug] [input:tail:tail.0] 1 new files found on path 'unicode_c.log'
[2024/10/07 16:01:31] [debug] [input:tail:tail.0] scanning path ../tests/runtime/data/tail/log/unicode_subdivision_flags_be.log
[2024/10/07 16:01:31] [debug] [input:tail:tail.0] file will be read in POSIX_FADV_DONTNEED mode ../tests/runtime/data/tail/log/unicode_subdivision_flags_be.log
[2024/10/07 16:01:31] [debug] [input:tail:tail.0] inode=43166609 with offset=0 appended as ../tests/runtime/data/tail/log/unicode_subdivision_flags_be.log
[2024/10/07 16:01:31] [debug] [input:tail:tail.0] scan_glob add(): ../tests/runtime/data/tail/log/unicode_subdivision_flags_be.log, inode 43166609
[2024/10/07 16:01:31] [debug] [input:tail:tail.0] 1 new files found on path '../tests/runtime/data/tail/log/unicode_subdivision_flags_be.log'
[2024/10/07 16:01:31] [ info] [output:stdout:stdout.0] worker #0 started
[2024/10/07 16:01:31] [debug] [stdout:stdout.0] created event channels: read=34 write=35
[2024/10/07 16:01:31] [ info] [sp] stream processor started
[2024/10/07 16:01:31] [debug] [input:tail:tail.0] [static files] processed 155b
[2024/10/07 16:01:31] [debug] [input:tail:tail.0] inode=42736996 file=unicode_c.log promote to TAIL_EVENT
[2024/10/07 16:01:31] [ info] [input:tail:tail.0] inotify_fs_add(): inode=42736996 watch_fd=1 name=unicode_c.log
[2024/10/07 16:01:31] [debug] [input:tail:tail.0] inode=43166609 file=../tests/runtime/data/tail/log/unicode_subdivision_flags_be.log promote to TAIL_EVENT
[2024/10/07 16:01:31] [ info] [input:tail:tail.0] inotify_fs_add(): inode=43166609 watch_fd=2 name=../tests/runtime/data/tail/log/unicode_subdivision_flags_be.log
[2024/10/07 16:01:31] [debug] [input:tail:tail.0] [static files] processed 0b, done
[2024/10/07 16:01:31] [debug] [task] created task=0x616b610 id=0 OK
[0] tail.0: [[1728284491.453318636, {}], {"log"=>"用汉字在 Fluent Bit 中处理日志，就像是一个梦一样😀"}]
[1] tail.0: [[1728284491.485253961, {}], {"log"=>"🏴󠁧󠁢󠁷󠁬󠁳󠁿🏴󠁧󠁢󠁳󠁣󠁴󠁿🏴󠁧󠁢󠁥󠁮󠁧󠁿"}]
[2024/10/07 16:01:31] [debug] [output:stdout:stdout.0] task_id=0 assigned to thread #0
[2024/10/07 16:01:31] [debug] [out flush] cb_destroy coro_id=0
[2024/10/07 16:01:31] [debug] [task] destroy task=0x616b610 (task_id=0)
^C[2024/10/07 16:01:32] [engine] caught signal (SIGINT)
[2024/10/07 16:01:32] [ warn] [engine] service will shutdown in max 5 seconds
[2024/10/07 16:01:32] [ info] [input] pausing tail.0
[2024/10/07 16:01:32] [ info] [engine] service has stopped (0 pending tasks)
[2024/10/07 16:01:32] [ info] [input] pausing tail.0
[2024/10/07 16:01:32] [ info] [output:stdout:stdout.0] thread worker #0 stopping...
[2024/10/07 16:01:32] [ info] [output:stdout:stdout.0] thread worker #0 stopped
[2024/10/07 16:01:32] [debug] [input:tail:tail.0] inode=42736996 removing file name unicode_c.log
[2024/10/07 16:01:32] [ info] [input:tail:tail.0] inotify_fs_remove(): inode=42736996 watch_fd=1
[2024/10/07 16:01:32] [debug] [input:tail:tail.0] inode=43166609 removing file name ../tests/runtime/data/tail/log/unicode_subdivision_flags_be.log
[2024/10/07 16:01:32] [ info] [input:tail:tail.0] inotify_fs_remove(): inode=43166609 watch_fd=2

• Attached Valgrind output that shows no leaks or memory corruption was found

==3616809== 
==3616809== HEAP SUMMARY:
==3616809==     in use at exit: 0 bytes in 0 blocks
==3616809==   total heap usage: 3,183 allocs, 3,183 frees, 989,783 bytes allocated
==3616809== 
==3616809== All heap blocks were freed -- no leaks are possible
==3616809== 
==3616809== For lists of detected and suppressed errors, rerun with: -s
==3616809== ERROR SUMMARY: 0 errors from 0 contexts (suppressed: 0 from 0)

If this is a change to packaging of containers or native binaries then please confirm it works for all targets.

• Run local packaging test showing all targets (including any new ones) build.
• Set ok-package-test label to test for all targets (requires maintainer to do).

Documentation

• Documentation required for this feature

fluent/fluent-bit-docs#1471

Backporting

• Backport to latest stable release.

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Fluent Bit is licensed under Apache 2.0, by submitting this pull request I understand that this code will be released under the terms of that license.