[compiler-rt] [sanitizer] Remove GetCurrentThread nullness checks from Allocate (PR #102828)

[Alexander Shaposhnikov via llvm-commits]

alexander-shaposhnikov wrote:

wondering if it's initialized if threads are created by direct calls of `clone` ?
(i guess this happens very rarely, but potentially it is possible)

https://github.com/llvm/llvm-project/pull/102828