H.264 uses a 16-pixel alignment, and the stream sink media type should have the aligned height after the session has started.
-- v14: mf/tests: Test H.264 decoder alignment. mf/tests: Test H.264 sink media type height alignment. mf/tests: Fix occasional hangs in test_media_session_source_shutdown(). mf/tests: Skip the scheme resolver tests if network connectivity is unavailable.