feat(allocator): add Allocator::alloc_bytes_start method

[overlookmotel]

Add an unsafe Allocator::alloc_bytes_start method. This method allows allocating space at the start of an Allocator's data chunk (instead of at the end as usually happens). We'll use this in linter JS plugins prototype for writing source text into start of arena, which is what raw transfer needs.

[overlookmotel]

• feat(napi/oxlint): read source text into start of allocator #12122
• feat(allocator): add Allocator::alloc_bytes_start method #12083 👈 (View in Graphite)
• feat(allocator): fixed size allocators #12082
• refactor(allocator): add AllocatorWrapper abstraction to AllocatorPool #12081
• test(napi/oxlint): test linting with built-in rules #12149
• main

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[codspeed-hq]

CodSpeed Instrumentation Performance Report

Merging #12083 will not alter performance

_{Comparing 07-04-feat_allocator_add_allocator_set_data_ptr_method (8d710a2) with main (c186bd8)}

Summary

✅ 34 untouched benchmarks

[camc314]

Merge activity

• Jul 9, 8:49 AM UTC: The merge label '0-merge' was detected. This PR will be added to the Graphite merge queue once it meets the requirements.
• Jul 9, 8:49 AM UTC: camc314 added this pull request to the Graphite merge queue.
• Jul 9, 9:07 AM UTC: Merged by the Graphite merge queue.