MCInstrDesc: Flags (uint64_t) was checked using (1 << MCID::XYZ), but this

should have been (1ULL << MCID::XYZ). Currently this works because enum Flag
has 31 values, but extending it will result in a compile warnings/errors.
This was part of the accepted patch in https://reviews.llvm.org/D23601, but
it was suggested to apply this first as a separate patch.

llvm-svn: 281149