[clang] [Android] Drop workarounds for older Android API levels pre 23 (PR #161893)

[Shoaib Meenai via cfe-commits]

smeenai wrote:

> Based on @smeenai's comment in [#161911 (comment)](https://github.com/llvm/llvm-project/pull/161911#issuecomment-3367569598), looks like we cannot yet assume 23+ for Android.

Thank you very much for the accommodation here! I'm raising this internally, so we can figure out how to handle this on our end.

If possible, could we hold off on this until after the LLVM 22 release branch is cut (usually around mid-January)? That'll give us some extra time for this.

https://github.com/llvm/llvm-project/pull/161893