Some debug code was enabled that prevented illegal instructions
from being handled normally with a processor exception
The brief instruction word decoding could cause an illegal instruction
if it didn't match the docs, but the actual implementation would not
complain in those cases, so I modified it to not perform validation
for <=MC68010
Increment and Decrement addressing modes, when using the stack pointer,
will always inc/dec by at least 2 bytes, even if it's a byte operation,
to keep the stack aligned to the nearest word boundary
