Revert "matroskamux: adjust unit test to modified behaviour"
Revert "matroskamux: adjust unit test to modified behaviour"

This reverts commit 8fe478c8a7746cd2c63f20d23e97e26e1a0e6192.

We're back to previous behaviour

stfl/gst-plugins-good,stfl/gst-plugins-good,stfl/gst-plugins-good,stfl/gst-plugins-good