Change the name of the file where to store the results
of the valgrind run.
Previously the file had a prefix "valgrind-", which is inconvinient.
Instead, have the file using the same name as the test executable,
with a ".valgrind-log" suffix.
When you want to run valgrind for a test, you either had to
invoke valgrind manually, or doing it via `make check` (provided
you configured --with-valgrind).
Make it more convenient to run valgrind by passing the test
to run to the "run-test-valgrind.sh" wrapper.
This also allows to pass -p/-s to the test, which is not possible
during `make check` because selecting tests conflicts with "--tap".
The following invocations are largely equivalent and work as
expected:
$ ./tools/run-test-valgrind.sh ./src/platform/tests/test-link-linux -p /link/software/detect/vlan
$ NMTST_DEBUG=no-debug,p=/link/software/detect/vlan ./tools/run-test-valgrind.sh ./src/platform/tests/test-link-linux
If the valgrind logfile is empty, don't log an error message with
the location of the logfile.
Also, if the test didn't fail due to memleaks, log a different message.
When configuring with --with-valgrind, tests will be invoked
via valgrind. That significantly slows down the tests. Allow
user to set the environment variable NMTST_NO_VALGRIND to invoke
tests directly, even when valgrind was enabled at configure time.
