[VL] Refactor HashTableBuilder to use Velox API

[JkSelf]

What changes are proposed in this pull request?

1. HashTableBuilder can directly call Velox API after refactor(hashjoin): Refactor hashJoinTableType and isLeftNullAwareJoinWithFilter API in HashJoinBridge facebookincubator/velox#18322 merged.
2. Fix following warning :

[85/132] Building CXX object velox/CMakeFiles/velox.dir/jni/VeloxJniWrapper.cc.o

/Users/kejia/github/bob/incubator-gluten/cpp/velox/jni/VeloxJniWrapper.cc:1112:24: warning: moving a temporary object prevents copy elision [-Wpessimizing-move]

 1112 |       otherTables[t] = std::move(hashTableBuilders[t]->uniqueTable());

      |                        ^

/Users/kejia/github/bob/incubator-gluten/cpp/velox/jni/VeloxJniWrapper.cc:1112:24: note: remove std::move call here

 1112 |       otherTables[t] = std::move(hashTableBuilders[t]->uniqueTable());

      |                        ^~~~~~~~~~                                   ~

1 warning generated. 

How was this patch tested?

Existing unit tests

Was this patch authored or co-authored using generative AI tooling?

No

[Copilot]

Pull request overview

This PR updates Gluten’s Velox hash join build path to rely on newly available Velox-side helpers, reducing local duplicated logic and addressing a compiler warning in the JNI builder.

Changes:

• Switch HashTableBuilder to call Velox-provided exec::hashJoinTableType and exec::isLeftNullAwareJoinWithFilter instead of maintaining local equivalents.
• Fix a -Wpessimizing-move warning in VeloxJniWrapper by removing an unnecessary std::move on a temporary unique_ptr return value.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated no comments.

File	Description
cpp/velox/operators/hashjoin/HashTableBuilder.cc	Removes local helper implementations and calls the corresponding Velox exec APIs for join table type construction and null-aware join handling.
cpp/velox/jni/VeloxJniWrapper.cc	Removes redundant std::move to avoid pessimizing-move warning when assigning the uniqueTable() return value.

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[Copilot]

Pull request overview

Copilot reviewed 2 out of 2 changed files in this pull request and generated no new comments.