Allow step/run when two breakpoints trip.

If a memcheck and breakpoint were triggered on the same line, you wouldn't
be able to pass it, which is probably not what you'd expect.
Debugger: fix "run to here" functionality.
Make memchecks ignore cached/uncached memory.

You usually want both.
Merge pull request #4342 from unknownbrackets/debugger

Ingore the uncached flag for memchecks, minor tweaks