test: make the test case failure output easier to select
Split the suite and test case name up so it's easier to select with a double-click in the terminal. Because usually those tests need to be re-run individually and making that easier is a good thing.
Previously: :: Failure: ../test/test-tablet.c:4434:touch_arbitration:wacom-cintiq-13hdt-pen-tablet
Now: :: Failure: ../test/test-tablet.c:4434: touch_arbitration(wacom-cintiq-13hdt-pen-tablet)