tests: Improve build of cmph tests in girepository
They were still failing with -Dglib_assert=false
because
G_DISABLE_ASSERT
wasn’t being explicitly un-defined for the test.
See https://gitlab.gnome.org/GNOME/glib/-/jobs/3309889
Also while we’re there, take the opportunity to correctly set the test suite, protocol and environment.
Signed-off-by: Philip Withnall pwithnall@gnome.org