[llvm] [llvm] Ensure newline at the end of files (NFC) (PR #143061)

[Matt Arsenault via llvm-commits]

arsenm wrote:

> Do we have an actual policy on whether or not files should have newlines at EOF? Last time I went through the programmer's manual/developer policy/coding standards I don't remember seeing anything.

Github marks it as an error if it's not missing so it should be there 

https://github.com/llvm/llvm-project/pull/143061