[compiler-rt] [scudo] Add hooks to mark the range of realloc (PR #74353)

[Christopher Ferris via llvm-commits]

cferris1000 wrote:

Fabio, since you are the person who is most interested in this change, can you indicate how this solves your problem? For example, it's not clear how a snapshot from a profiler potentially being slightly wrong if it gets caught between the deallocate hook and the allocate hook in the realloc code is a problem. I'm not familiar with the profilers and how they are used by your team, so this could be something that occurs frequently. If you are using a sampler profiler, there is always the possibility of a snapshot being incorrect since you could get caught before the hook is called but after the operation has completed depending on how the profiler is coded.

I'm not opposed to this change, I just want to make sure we are adding code that solves a real problem, and not adding code for a corner case that is not an issue for any current profilers.

https://github.com/llvm/llvm-project/pull/74353