Refactor MixedBulkWriteOperation to simplify retry logic there

[stIncMale]

For reviewers

I recommend reviewing the changes commit by commit. Review the sync code changes to assess the correctness compared to the pre-PR code. Then review the async code changes to assess whether the sync code was correctly translated into the async code.

Ignore the ServerDiscoveryAndMonitoringProseTests.testConnectionPoolBackpressure Evergreen failures. There are unrelated and we'll deal with them separately.

AI usage

All the changes were handmade. AI was used only to review the changes.

JAVA-6218

[Copilot]

Pull request overview

This PR refactors MixedBulkWriteOperation retry handling to use per-batch RetryState instances and shared retry helpers, while updating related helper APIs, tests, and async control-flow conventions.

Changes:

• Reworks mixed bulk write sync/async retry flow and removes the custom bulk-write retry tracker.
• Updates shared retry/helper APIs and callers for source/connection handling and retry failure bookkeeping.
• Adjusts functional/unit tests and shared test utilities to reflect the new retry/resource lifecycle.

Reviewed changes

Copilot reviewed 17 out of 17 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
driver-core/src/main/com/mongodb/internal/operation/MixedBulkWriteOperation.java	Refactors bulk write batching, retry, async execution, and resource holder logic.
driver-core/src/main/com/mongodb/internal/operation/SyncOperationHelper.java	Reorders withSourceAndConnection parameters and updates retry failure handling.
driver-core/src/main/com/mongodb/internal/operation/AsyncOperationHelper.java	Updates async retry failure handling and helper signatures.
driver-core/src/main/com/mongodb/internal/operation/CommandOperationHelper.java	Renames retry-label helper and passes server deprioritization directly.
driver-core/src/main/com/mongodb/internal/operation/ClientBulkWriteOperation.java	Aligns helper usage and async control flow with the refactored retry helpers.
driver-core/src/main/com/mongodb/internal/operation/retry/AttachmentKeys.java	Removes obsolete bulk write tracker attachment key.
driver-core/src/main/com/mongodb/internal/async/function/RetryState.java	Removes external last-attempt marking API.
driver-core/src/main/com/mongodb/internal/async/AsyncRunnable.java	Documents MutableValue usage in async lambdas.
driver-core/src/main/com/mongodb/internal/operation/FindOperation.java	Updates withSourceAndConnection call signature.
driver-core/src/main/com/mongodb/internal/operation/ListCollectionsOperation.java	Updates withSourceAndConnection call signature.
driver-core/src/main/com/mongodb/internal/operation/ListIndexesOperation.java	Updates withSourceAndConnection call signature.
driver-core/src/test/functional/com/mongodb/OperationFunctionalSpecification.groovy	Adds configurable expected connection release counts.
driver-core/src/test/functional/com/mongodb/internal/operation/MixedBulkWriteOperationSpecification.groovy	Updates mixed bulk write retry expectations.
driver-core/src/test/unit/com/mongodb/internal/async/function/RetryStateTest.java	Removes tests for deleted markAsLastAttempt.
driver-sync/src/test/functional/com/mongodb/client/MongoWriteConcernWithResponseExceptionTest.java	Refactors test for sync/reactive reuse and failpoint listener utility.
driver-sync/src/test/functional/com/mongodb/client/FailPoint.java	Makes failpoint guard close idempotent.
driver-reactive-streams/src/test/functional/com/mongodb/reactivestreams/client/MongoWriteConcernWithResponseExceptionTest.java	Reuses sync test through reactive sync adapter override.

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[stIncMale]

The code is so good that Copilot failed to find anything! 💪 😃

[stIncMale]

TODO @stIncMale: delete OperationHelper.validateWriteRequestsAndCompleteIfInvalid.

@vbabanin Note that the beginAsync API allows us to use OperationHelper.validateWriteRequests in both sync and async implementations, so OperationHelper.validateWriteRequestsAndCompleteIfInvalid is no longer used, but I forgot to delete it.