[libclc] [libclc] Remove __attribute__((always_inline)) (PR #158791)

[Wenju He via cfe-commits]

wenju-he wrote:

@mgorny thank you for the testing. Sorry I didn't run the tests for this PR. 
The test failures will be fixed by https://github.com/llvm/llvm-project/pull/160036

https://github.com/llvm/llvm-project/pull/158791