Close exact-scoring vector suppliers and make thread-local cleanup exception-safe #764

Follow-up to #635 and #715 covering two existing lifecycle gaps. These are separate from #715's worker-draining and remapped-copy concerns.

1. Exact-scoring suppliers have no teardown path

BuildScoreProvider.randomAccessScoreProvider creates two thread-local vector suppliers. Neither the returned provider nor GraphIndexBuilder.close() releases those suppliers; builder.close() only closes its searchers. Closing the separate insertion supplier in #715 therefore leaves the scoring copies unclosed.

Reproduced against the unmodified #715 source snapshot (264979e), with a shared AutoCloseable RAVV that counts copy/close calls, a single-worker pool, and an exact-scoring build followed by builder.close(): 3 copies created, 1 closed, 2 unclosed. Current main retains the same ownership gap.

Define an explicit ownership/teardown path for library-owned scoring suppliers, retaining their availability through final scoring and graph cleanup. Preserve caller ownership of the source and externally supplied providers. Audit the bounded VectorAccess supplier callers introduced by #744 for the same gap.

2. A throwing close skips remaining copies and cache clearing

ExplicitThreadLocal.close() exits immediately if one value's close() throws. Remaining values are never attempted and map.clear() is skipped. The new ThreadLocalCopies.close() in #715 delegates directly to this method.

Reproduction: populate the supplier from two dedicated worker threads, make both copies' close() throw, then close the supplier after the workers finish. Observed: 2 copies created, only 1 close attempted.

Attempt every close, reliably clear the cache, and aggregate failures with suppressed exceptions. Call sites should also preserve an original operation failure if cleanup fails.

Validation

• Add an exact-scoring build/teardown test that verifies all owned copies are released while the caller-owned source remains usable.
• Add a multi-copy throwing-close test verifying every close is attempted, the cache is cleared, and failures remain inspectable.
• Exercise the supported supplier reuse-after-close behavior after a cleanup failure.

The targeted reproductions ran on OpenJDK 23.0.1 with the scalar provider and assertions enabled. The PR's three added TestThreadLocalCopies tests pass, but do not cover these cases.