CNDB-11016: Parallelized compactions

[blambov]

What is the issue

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What does this PR fix and why was it fixed

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Checklist before you submit for review

• Make sure there is a PR in the CNDB project updating the Converged Cassandra version
• Use NoSpamLogger for log lines that may appear frequently in the logs
• Verify test results on Butler
• Test coverage for new/modified code is > 80%
• Proper code formatting
• Proper title for each commit staring with the project-issue number, like CNDB-1234
• Each commit has a meaningful description
• Each commit is not very long and contains related changes
• Renames, moves and reformatting are in distinct commits

[sonarcloud]

Quality Gate failed

Failed conditions
56.3% Coverage on New Code (required ≥ 80%)

See analysis details on SonarQube Cloud

[cassci-bot]

❌ Build ds-cassandra-pr-gate/PR-1416 rejected by Butler

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18 new test failure(s) in 7 builds
See build details here

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Found 18 new test failures

Showing only first 15 new test failures

Test	Explanation	Branch history	Upstream history
...istributed.test.ReadRepairCollectionQueriesTest	regression	🔴🔵🔵🔴🔴🔵🔵
t.TestCqlshUnicode.test_unicode_desc	regression	🔴🔴🔵🔵🔴🔴🔵
t.TestCqlshUnicode.test_unicode_identifier	flaky	🔴🔵🔴🔴🔴🔵🔴
t.TestCqlshUnicode.test_unicode_multiline_input	regression	🔴🔵🔵🔴🔴🔵🔴
t.TestCqlshUnicode.test_unicode_value_round_trip	regression	🔴🔴🔵🔴🔴🔴🔴
...oadCommitLogAndSSTablesWithDroppedColumnTestDSE	failing	🔴🔴🔴🔴🔴🔴🔴
...ToolEnableDisableBinaryTest.testMaybeChangeDocs	regression	🔴🔵🔵🔵
o.a.c.d.t.s.TraceTest.testMultiIndexTracing	regression	🔴🔵🔵🔴
...set=timeuuid,wide=false,scenario=SSTABLE_QUERY]	flaky	🔵🔴🔵🔵
...list>,wide=false,scenario=COMPACTED_QUERY]	regression	🔴🔵🔵🔵
...aset=list,wide=true,scenario=MIXED_QUERY]	flaky	🔵🔴🔵🔵
...ozen<set>>,wide=true,scenario=MIXED_QUERY]	flaky	🔵🔴🔵🔵
...frozen,wide=false,scenario=SSTABLE_QUERY]	flaky	🔵🔴🔵🔵
...t.testKDTreePostingsQueryMetricsWithSingleIndex	failing	🔴🔴🔴🔴🔴🔴🔴
...m.TrieMemtableMetricsTest.testContentionMetrics	regression	🔴🔵🔵🔵

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Found 13 known test failures