tests: make signal other than ABRT a hard failure

tests: make signal other than ABRT a hard failure

We handle FAIL_TEST tests by simply inverting the success flag. The
problem with this is, that if a FAIL_TEST fails by a SIGSEGV, it will be
interpreted as passed. However, no code should ever cause a SEGV, or any
other signal than ABRT. And even ABRT only in the case of an assert()
that is meant to fail. We would probably need more sophistication for the
FAIL_TEST cases.

For now, just interpret any other signal than ABRT as a hard failure,
regardless whether it is a TEST or FAIL_TEST. At least segfaults do not
cause false passes anymore.

Signed-off-by: Pekka Paalanen <ppaalanen@gmail.com>