It was only in RISCVInstrInfo because it was used by 2 passes, but those
passes have been merged in D147173.
Reviewed By: asb
Differential Revision: https://reviews.llvm.org/D147174
These run together in the pipeline and are the only users of
TII.hasAllWUsers. Merging them will allow us to move hasAllWUsers
back from TII.
Reviewed By: asb
Differential Revision: https://reviews.llvm.org/D147173