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 10 minutes and 2 seconds (queued for 3 seconds)
Status Job ID Name Coverage
  Build
passed #275222
build-mutter

00:02:49

 
  Test
passed #275223
test-mutter

00:07:13