[llvm] [MC] Make .note.GNU-stack explicit for the trampoline case (PR #151754)

[Matt Arsenault via llvm-commits]

arsenm wrote:

> Thank you for letting me know, @arsenm. Is there a link to the buildbot log? I thought I removed all the traces of 'getNonexecutableStackSection'. I can revert while I investigate.

Not sure there' a bot, we have fairly poor macOS bot coverage. touching those targets MCTargetDesc seems to have worked, so maybe there's a cmake issue somewhere? 

https://github.com/llvm/llvm-project/pull/151754