changes some of the test commands to use bash functions
includes some small bug fixes to tests where bugs were
previously not seen due to different plumbing.
Also a couple of changes to testbench worth mentioning:
* use cp -f to ensure files can be overwirtten in VBUILD
* fix issue of missing include test file in EXTRA_DIST
* new supressions
* testbench: try to use local system dependency cache
avoid going to Internet repos if not absolutely necessary. For
development containers, they should be pre-populated with the
important dependencies.
* do not enable libfaketime if ASAN is selected
unfortunately, libfaketime does not work in that case
see also https://github.com/rsyslog/rsyslog/issues/174
