[Parallel Executor] MvHashMapView should not be sync

[gelash]

🚀 Feature Request

MvHashMapView is used by only a single thread during parallel execution to interface with the multi-version data-structure and capture the read set and dependencies. It currently has to be Sync due to some StateSync/VersionedView trait bounds.

Then read_dependency member can be RefCell and captured reads can also be a RefCell instead of a mutex.

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