Michal Nowak authored Jun 22, 2020 and Michał Kępień committed Jul 17, 2020

Make sure bin/tests/system/run.sh returns a non-zero exit code if any of
the following happens:

  - the test being run produces a core dump,
  - assertion failures are found in the test's logs,
  - ThreadSanitizer reports are found after the test completes,
  - the servers started by the test fail to shut down cleanly.

This change is necessary to always fail a test in such cases (before the
migration to Automake, test failures were determined based on the
presence of "R:<test-name>:FAIL" lines in the test suite output and thus
it was not necessary for bin/tests/system/run.sh to return a non-zero
exit code).