release-26aa71d: Use clang-5.0 -Oz

Summary:
Use clang-5.0 -Oz as default NDK compiler for android.
It does 3 good things:
* brings us into compliance with deprecation of gcc for android NDKs since r13
* yields slightly smaller native code, on the order of many-10s-to-small-100s of KB
* slight improvement in startup performance, on the order of 10s of ms

Reviewed By: mzlee

Differential Revision: D6155682

fbshipit-source-id: 2f64e742f4dc44be171274c2ad0a41fb1e7079d7

release-8a6a711: Fix get_library_mapping_address()

Summary: update sscanf format to parse hex address properly

Differential Revision: D6487828

fbshipit-source-id: 72a886f9ae8fcafc6d36d346d848133fe90f80e2

release-7900772: Instrument IOs via PLT hooks

Summary:
-> Create new provider
-> Hook libc open/read/write/close/etc
-> Trace output should be of the form "func(<path>)"

Differential Revision: D6222867

fbshipit-source-id: efa483af2c48edf740c82436e9328dd696bd33ae

release-ca87e97: Fix Android comment and docblock typos

Summary:
:wave: Hello! Thanks for react-native, it’s a great project.

I was digging into the Android implementation in _ReactAndroid_ and noticed a couple typos in the documentation. I went through and tried to fix all the typos I could find using [aspell](http://aspell.net).

Not applicable: these changes are only to comments, and CI should be skipped.

[ANDROID][ENHANCEMENT][*] - Correct comment and docblock typos
Closes https://github.com/facebook/react-native/pull/17049

Differential Revision: D6472182

Pulled By: shergin

fbshipit-source-id: 7e62cab118609596b483d1cf16c3abf651d6753b

release-782ef18: Initial Loom python utility script

Summary:
Adds
 - struct for `DeviceTrace`
 - function to list traces on device
 - ability to pull a specific trace

Notes
 - error handling is minimal, happy to add something more robust but preferred to put up something more minimal to start.
 - the package name needs to be provided. I could grab the package of the focused activity if we want to add that. It felt more hacky than I'd like and it's not required so I omitted it for now.

{gif:7ooq6lgj}

Reviewed By: BurntBrunch

Differential Revision: D6425982

fbshipit-source-id: 16e4f93dbe68a32c6a13217cc3831764f348e0bf

release-36ec828: Bump up Loom thread priority as an experiment.

Summary: Bump loom thread priority from Process.THREAD_PRIORITY_BACKGROUND - 1 to Process.THREAD_PRIORITY_BACKGROUND - 5.

Reviewed By: BurntBrunch

Differential Revision: D6465151

fbshipit-source-id: 1744c0400607229cb6d6c17d8c30746198b055cc

release-1e67646: Skylarkify robolectric3_test.

Reviewed By: adamjernst

Differential Revision: D6453041

fbshipit-source-id: 6d180dfbc4afd2b15fa124ef5779a5d7a49b5658

release-a20cc40: Assign releases to the right commit

Summary:
This was a tough one. It took about 20 builds and reading the github docs to
figure out wtf is going on.

1) Travis needs a tag to even start the deployment.
2) Adding a tag to the local Travis checkout works fine.
3) However, upon receipt of the Travis request to create a new release, Github,
not being aware of this tag (since Travis can't push it to github), defaults to
creating it on master. Wherever master is pointing right now.

The fix is to specify the `target_commitish` argument explicitly.
Separately, we create a better name for the tag - something like
`release-<shortrev>` rather than the mess travis generates.

Also, let's disable email notifications for successful builds while we're here.
Also-also, let's not start the build again once github pushes the tag, that's
silly.

Differential Revision:
D6456285
Ninja: oss build stuff

fbshipit-source-id: 3318d0c2a24ee21dc73d2ab0ce81b6b1896b5375