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

[via llvm-commits]

Un1q32 wrote:

A quick look through LLVM's code shows the only logic to get the linker version for Darwin targets is in Clang, porting it over to LLVM would require more knowledge of the codebase than I currently have.  Maybe another time.

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