[llvm] Remove iOS 5 check for tailcalls on ARM (PR #133354)

[via llvm-commits]

Un1q32 wrote:

> Wait, sorry, I misspoke. It was the static linker at the time that didn't support it, and support landed in ld64-124.1 per rdar://9116044.

Maybe I should change the check to make sure the linker version is at least 124.1 instead of removing the check entirely then.

https://github.com/llvm/llvm-project/pull/133354