when all elements are integers and no block is given, use
specialized heapify/insertion_sort that compare mrb_int values
directly, bypassing sort_cmp entirely. this eliminates per-comparison
overhead of GC arena save/restore, type checking, and array
modification checks.
the pre-scan to detect all-integer arrays is O(n), negligible
compared to O(n log n) sort. non-integer and block sorts are
unaffected.
Co-authored-by: Claude <noreply@anthropic.com>
Yukihiro "Matz" Matsumoto
5364c4167e