[AArch32] Fix a stupid error in an architectural guard

The < 8 instead of <= 8 meant that a bunch of vreinterprets were not available on v8 AArch32. Simplify the guard to just !defined(aarch64) while we're at it, and enable some v8 AArch32 testing.



git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@211686 91177308-0d34-0410-b5e6-96231b3b80d8