[PATCH 18/18] Introduce catchpoint class

[Tom Tromey]

Simon> This causes some regressions:

It turns out my test-result comparison script doesn't really note gdb
crashes.  They probably show up under "missing tests" -- but I've gotten
a bit too used to just ignoring that.

It would be better if a crash always showed up as a FAIL.

Anyway... still my fault, I'm not trying to shift the blame.

I'll send the fix shortly.

Tom