Implement address and data triggers.

Implement address and data triggers.

So far I only have testcases for instruction and data address.
Not implemented is the mechanism that lets the debugger prevent a user
program from using triggers at all. I'll be adding that soonish.

The critical path is unchanged, but my experimenting shows the
simulation is slowed down about 8% by this code. Reducing the size of
trigger_match() (which is never called during my benchmark) fixes that,
but making it not be inlined has no effect. I suspect the slowdown comes
from cache alignment or something similar, and on a different CPU or
after more code changes the speed will come back.