[PATCH] test: atomicity.py: improve exit probability on failure

[David Bremner]

Tomi Ollila <tomi.ollila at iki.fi> writes:

> Some gdb python exceptions on some os environments (e.g. macOS
> Sierra, non-codesigned gdb) do not make gdb exit (but to drop down
> to nonexistent command line?).
> Mitigate this chance by explict SystemExit on all exceptions.
> The contents of output file 'gdb.out' is unchanged.

pushed to master

d