NEON immediates are "interesting". Start of the work to handle parsing them
in an 'as' compatible manner. Getting the matcher to play nicely with
these and the floating point immediates from VFP is an extra fun wrinkle.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@142293 91177308-0d34-0410-b5e6-96231b3b80d8