[clang] [libclc] libclc: remove __attribute__((assume)) for clspv targets (PR #92126)

[Erich Keane via cfe-commits]

https://github.com/erichkeane commented:

Also needs:
-a release note
-A test: At least a test against LLVM-IR (CodeGen test).

https://github.com/llvm/llvm-project/pull/92126