Instead of using an environment variable, pass the path to the config
file as a command line argument. This makes it possible to directly
copy the command being run (as show with --verbose) and run it in a
debugger outside of the test framework.
Old verbose output:
Running: /home/ajor/src/object-introspection3/build/test/integration/integration_test_target oil cycles_unique_ptr
New verbose output:
Running: /home/ajor/src/object-introspection3/build/test/integration/integration_test_target oil cycles_unique_ptr /home/ajor/src/object-introspection3/build/testing.oid.toml
The `oil_skip` test option was added for tests that don't work under OIL
but do work under OID. However, we now have two classes of `oil_skip`ped
tests: those that could be fixed, and those that will never work.
Increase clarity by not generating the tests which do not make sense at
all, leaving us with a cleaner set of skipped (and fixable) tests.
