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

[Chris Apple via llvm-commits]

cjappl wrote:

Thanks @MaskRay ! We were unsure of what to do when it looked like there was some approval, but we didn't have merge rights. Thanks for your help as always

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