refactor(array): use buffer allocator in execution context

[gatesn]

Summary

Add a buffer allocator to execution and I/O contexts.

Changes

• Store BufferAllocatorRef in ExecutionContext.
• Use it for chunked canonicalization.
• Allocate file and object-store reads with the caller allocator.
• Remove the old array memory allocator wrapper.

[codspeed-hq]

Merging this PR will improve performance by 60.69%

⚠️ Unknown Walltime execution environment detected

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⚠️ Different runtime environments detected

Some benchmarks with significant performance changes were compared across different runtime environments,
which may affect the accuracy of the results.

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⚡ 1 improved benchmark
✅ 2171 untouched benchmarks
⏩ 206 skipped benchmarks¹

Performance Changes

	Mode	Benchmark	BASE	HEAD	Efficiency
⚡	WallTime	arrow_checked_add_u32_neon[16384]	20.5 µs	12.7 µs	+60.69%

Tip

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_{Comparing ngates/buffer-allocator-context (c79a228) with develop (98dd977)}

Footnotes

1. 206 benchmarks were skipped, so the baseline results were used instead. If they were deleted from the codebase, click here and archive them to remove them from the performance reports. ↩