[AARCH64 folding] Do not fold any copy with NZCV

There is no instruction to fold NZCV, so, just do not do it.

Without the fix the added test case crashes with an assert
"Mismatched register size in non subreg COPY"

Reviewed By: danilaml
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D127294