Verify texImage3D and texSubImage3D code paths taking video elements (RGBA16F/RGBA/HALF_FLOAT)

On success, you will see a series of "PASS" messages, followed by "TEST COMPLETE".

testing: video/mp4; codecs="avc1.42E01E, mp4a.40.2"
FAIL video.play failed: NotSupportedError: Failed to load because no supported source was found.