To increase the effective test coverage, this patch
re-enables the tst_qopengl test case as such, and
instead disables only the test functions that are currently
failing in CI.
Task-number: QTBUG-22453
Change-Id: Ifa9ccab81efb1577767465c150fc64a9d9e3f8e0
Reviewed-by: Toby Tomkins <toby.tomkins@nokia.com>