[compiler-rt] [compiler-rt][rtsan] Use sanitizer internal allocator during rtsan init to avoid segfault in dlsym (PR #98679)

[Fangrui Song via llvm-commits]

MaskRay wrote:

I was waiting for possible response from regular compiler-rt sanitizers folks:) I think this is good to merge in the absence of their response.

https://github.com/llvm/llvm-project/pull/98679