[llvm] [AArch64] AArch64TargetLowering::computeKnownBitsForTargetNode - add support for AArch64ISD::MOV/MVN constants (PR #154039)

[Yatao Wang via llvm-commits]

ningxinr wrote:

This patch may have caused bot failures, e.g. [sanitizer-aarch64-linux-bootstrap-ubsan](https://lab.llvm.org/buildbot/#/builders/85/builds/12699). I am investigating. 

https://github.com/llvm/llvm-project/pull/154039