segment: update the tests
segment: update the tests

Boy scout rule. Make is a little less painful to debug the tests by using
fail_unless_equals_{uint64,int64,float} where appropriate. Ideally the large
tests would be splitted to avoid guessing data dependencies.

StreamUtils/gstreamer,StreamUtils/gstreamer,StreamUtils/gstreamer,StreamUtils/gstreamer,StreamUtils/gstreamer