[llvm] [AArch64] Lower cttz(bitcast <Nxi1> to iN) with shrn-based compressed movemask (PR #199081)

[Adam Scott via llvm-commits]

as4230 wrote:

> It looks like your email address is set to private; see https://llvm.org/docs/DeveloperPolicy.html#email-addresses .

Fixed. Local commits had my email but github account level email was private. Made public. 

https://github.com/llvm/llvm-project/pull/199081