for tw/twi instructions, force propagated constant into a register to avoid "a1 cannot be immediate" errors from the emitter
Fix twi/tw instructions being switched in Jit64 and JitArm; downgrade the ERROR_LOG printed when tw is ran in the interpreter to DEBUG
Merge pull request #1017 from zhuowei/tw_fallback_if_constant_ra

Fix various issues with the twi/tw instructions