cogl/tests: Use less verbose run-tests.sh on single tests run by meson

Use less verbose output when run-tests.sh is running only a test and we're
requested for less verbose output.

Also write the test name first of running it.

GNOME/mutter!442
2 jobs for meson-test-suites in 5 minutes and 13 seconds (queued for 2 seconds)
Status Job ID Name Coverage
  Build
passed #263840
build-mutter

00:02:27

 
  Test
passed #263841
test-mutter

00:02:46