Fix undefined behavior in AArch64

A64Imms::isLogicalImmBits and A64Imms::isLogicalImm will attempt to
execute shifts that perform undefined behavior. Instead of attempting
to perform the 64-bit rotation, treat it as a no-op.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@179317 91177308-0d34-0410-b5e6-96231b3b80d8