node:zlib: block worker shutdown on in-flight async compression (UAF) - #35155

The worker script exercises gzip/deflate (both → `NativeZlib`) and brotliCompress (→ `NativeBrotli`), but omits `zstdCompress` — so the `NativeZstd` task tag never reaches the barrier/drain, even though the PR description names zstd as an affected entry point and the fix is monomorphized for all three tags. Consider adding one more lane, e.g. `const zs = promisify(zlib.zstdCompress); lanes(1, () => zs(big.subarray(0, 4 << 20)));`, per REVIEW.md's "cover the variant matrix, not just the repro".

The explicit `30_000` per-test timeout violates test/CLAUDE.md ("**CRITICAL**: Do not set a timeout on tests") and REVIEW.md ("Don't raise per-test timeouts to make a slow test pass; shrink the workload"). The ~11s ASAN runtime comes from 4 rounds × 5 lanes over 4–16 MiB buffers; consider shrinking the buffers (e.g. 1–4 MiB — the lanes are already in flight when `"up"` arrives, so smaller chunks still land `terminate()` mid-`do_work()`) and/or trimming ROUNDS so it fits the default, then drop th