[TySan] Intercept malloc_size on Apple platforms. (#122133)
After https://github.com/llvm/llvm-project/pull/120563 malloc_size also
needs intercepting on Apple platforms, otherwise all type-sanitized
binaries crash on startup with an objc error:
realized class 0x12345 has corrupt data pointer: malloc_size(0x567) = 0
PR: https://github.com/llvm/llvm-project/pull/122133