add code to recognize memory stalls in resources and the pipeline as well
as squash a thread if there is a stall and we are in the switch on cache miss
model
add buffer for instructions to switch out to in a pipeline stage
can't squash the instruction and remove the pipeline so we kind of need
to 'suspend' an instruction at the stage while the memory stall resolves
for the switch on cache miss model
This model currently only works in MIPS_SE mode, so it will take some effort
to clean it up and make it generally useful. Hopefully people are willing to
help make that happen!
