Fix various issues with the twi/tw instructions

This patch fixes three issues with tw/twi emulation:

1: force propagated constant into register to avoid "a1 cannot be immediate" errors

Tw/twi is a "trap if comparison is true" instruction, which means that a cmp instruction is generated.
The emitter wants a register in the first argument to cmp, but constant propagation may try to pass in a constant instead.
For now, fall back to interpreter instead of displaying error: a proper way to translate this would be to load constant into a scratch register first like cmpXX does. 

Do games actually use these two instructions? I ran into this error when attempting to run Wii Linux.

2: tw/twi instruction are switched in Jit64 and JitArm
the twi instruction was generating the comparison instruction for tw, and vise versa. This corrects that mistake.

3: fix another potential logging spam in the interpreter when tw is run
#1011 got rid of the ERROR_LOG printed when twi is run in interpreter, but I missed the same logging that was present in tw. This downgrades that log to DEBUG_LOG also.
@zhuowei I am getting a PanicAlert on this line which says, "WriteNormalOp - a1 and a2 cannot both be memory".  Any ideas on a fix?