[clang] [AMDGPU] Do not enable GPU sanitizers by default (PR #126090)

[Yaxun Liu via cfe-commits]

yxsamliu wrote:

This may break ROCm santizer builds since whether santizer is on should be determined by -fsanitize only, i.e. by default -fgpu-sanitize should be on.

https://github.com/llvm/llvm-project/pull/126090