du: malloc perf +3~6% #11034

Performance Gate Passed

⚡ 4 improved benchmarks
✅ 284 untouched benchmarks
⏩ 40 skipped benchmarks¹

	Mode	Benchmark	`BASE`	`HEAD`	Efficiency
⚡	Simulation	`du_max_depth_balanced_tree[(6, 4, 10)]`	27 ms	25.9 ms	+4.18%
⚡	Simulation	`du_deep_tree[(100, 3)]`	1.2 ms	1.2 ms	+3.76%
⚡	Simulation	`du_summarize_balanced_tree[(5, 4, 10)]`	7 ms	6.7 ms	+4.27%
⚡	Simulation	`du_wide_tree[(5000, 500)]`	9.8 ms	9.3 ms	+5.84%

_{Comparing oech3:sort-0fill (d243986) with main (de5c827)}

40 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. ↩