tests: run-backtrace-demangle.sh check exitcode and max number of frames.

There can be more than 3 frames, but depending on the system/installed
glibc we might not be able to unwind fully till the end.
cxxfunc -> f -> main
Expect to see the top two and a warning that there are more frames
(exit code 1)

Signed-off-by: Mark Wielaard <mjw@redhat.com>
2 files changed