Rollup merge of #144364 - alexcrichton:update-dlmalloc, r=Mark-Simulacrum

Update `dlmalloc` dependency of libstd

This primarily pulls in alexcrichton/dlmalloc-rs#55 and alexcrichton/dlmalloc-rs#54 to address rust-lang/rust#144199. Notably the highest byte in the wasm address space is no longer allocatable and additionally the allocator internally uses `wrapping_add` instead of `add` on pointers since on 32-bit platforms offsets might be larger than half the address space.

Closes rust-lang/rust#144199