[ci] Add size-balanced test sequencer for better shard distribution #35458
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[ci] Increase DevTools test shards and bump timeout - Increase DevTools test shards from 3 to 5 - Bump timeout to 20s
Jest's default test sequencer sorts alphabetically, causing large test files (eg ReactDOMFloat-test.js at 9k lines, ReactHooksWithNoopRenderer-test.js at 4k lines) to cluster in shard 3/5. This made shard 3/5 average 117s vs 77s for other shards, a 52% slowdown. I'm using filesize as a rough proxy for number of tests. This custom sequencer sorts tests by file size and distributes large files evenly across all shards instead of clustering them together.
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[ci] Increase DevTools test shards and bump timeout - Increase DevTools test shards from 3 to 5 - Bump timeout to 20s --- [//]: # (BEGIN SAPLING FOOTER) Stack created with [Sapling](https://sapling-scm.com). Best reviewed with [ReviewStack](https://reviewstack.dev/facebook/react/pull/35459). * #35458 * __->__ #35459
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Jest's default test sequencer sorts alphabetically, causing large test files
(eg ReactDOMFloat-test.js at 9k lines, ReactHooksWithNoopRenderer-test.js at 4k
lines) to cluster in shard 3/5. This made shard 3/5 average 117s vs 77s for
other shards, a 52% slowdown. I'm using filesize as a rough proxy for number of tests.
This custom sequencer sorts tests by file size and distributes large files evenly across all shards
instead of clustering them together.
Stack created with Sapling. Best reviewed with ReviewStack.