fix: avoid buffer resize cost in shuffle reader during InMemoryPayload merge

[zhangxffff]

What problem does this PR solve?

Issue Number: close #545

Type of Change

• 🐛 Bug fix (non-breaking change which fixes an issue)
• ✨ New feature (non-breaking change which adds functionality)
• 🚀 Performance improvement (optimization)
• ⚠️ Breaking change (fix or feature that would cause existing functionality to change)
• 🔨 Refactoring (no logic changes)
• 🔧 Build/CI or Infrastructure changes
• 📝 Documentation only

Description

BoltColumnarBatchDeserializer::next() previously merged each inbound BlockPayload into a running merged_ InMemoryPayload immediately on arrival. With N small payloads consolidating into one output batch, this triggered N−1 calls to InMemoryPayload::merge(), and each call reallocated the destination buffer to exactly the new size — Arrow's PoolBuffer::Reserve does not grow capacity geometrically. The result was O(N) Arrow reallocations and O(N²) bytes copied per output batch.

This PR accumulate inbound payloads size, prealloc enough size and merge when the batch is ready.

Benchmark case: 4 columns with 1024 length StringView, each payload has 4 StringView. Read cost reduce from 14.68s to 131.26ms.

Performance Impact

• No Impact: This change does not affect the critical path (e.g., build system, doc, error handling).

• Positive Impact: I have run benchmarks.

  Click to view Benchmark Results

• Negative Impact: Explained below (e.g., trade-off for correctness).

Release Note

Please describe the changes in this PR

Release Note:

Release Note:
fix shuffle reader performance issue caused by memory reallocate

Checklist (For Author)

• I have added/updated unit tests (ctest).
• I have verified the code with local build (Release/Debug).
• I have run clang-format / linters.
• (Optional) I have run Sanitizers (ASAN/TSAN) locally for complex C++ changes.
• No need to test or manual test.

Breaking Changes

• No

• Yes (Description: ...)

  Click to view Breaking Changes

  Breaking Changes:
  - Description of the breaking change.
  - Possible solutions or workarounds.
  - Any other relevant information.