ARM64: Redundant movs can be eliminiated

[kunalspathak]

I have seen below pattern in generated code for framework libraries. We can eliminate 2nd move.

       AA0003F8          mov     x24, x0
       AA1803E0          mov     x0, x24

There are approx. 27K such patterns in 16K methods. Details in redundant-mov-2.txt.