Electron Releases

Description of Change

script/split-tests.js packed CI test shards from one weights table per platform, so a MAS job packed from darwin timings, an ASan job from plain Linux timings, and arm64 from x64. Those jobs differ by more than a constant factor, which left their shards uneven:

(median of the last three green push runs on main, test-step minutes)

• One table per test job, keyed as the job names its test_artifacts_* upload (darwin_x64, mas_arm64, linux_x64_asan, win_arm64, ...). CI already exports that key as ARTIFACT_KEY before the shard step.
• A job without a table falls back to the nearest one of its build type (same arch first; MAS to darwin), then to a legacy darwin/linux/win32 table, so nothing changes on a branch that has not regenerated yet.
• spec/index.js records the sanitizer in spec-timings.json; gen-spec-weights.js keys tables the same way and skips the Wayland allowlist job.
• Weights regenerated from every artifact of run 34181277552.

The tables will be kept fresh by a weekly roller (electron/roller) that regenerates each branch's file from its own recent runs and opens a PR when the packing has drifted.

Notes: none