[llvm] [AArch64] Fold vector select with power-of-2 bit-test to CMTST+BSP (PR #209100)

[David Green via llvm-commits]

https://github.com/davemgreen approved this pull request.

LGTM providing that the test are all passing. Thanks for putting up with the requests.

https://github.com/llvm/llvm-project/pull/209100