AArch64: Make test more robust.

AArch64: Make test more robust.

Avoid the creation of select instructions which can result in different
scheduling of the selects.

I also added a bunch of additional store volatiles. Those avoid A
CodeGen problem (bug?) where normalizes and denomarlizing the control
moves all shift instructions into the first block where ISel can't match
them together with the cmps.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@228362 91177308-0d34-0410-b5e6-96231b3b80d8