Revert "qtdemux: fix conditions for end of segment in reverse playback" to fix edit list regression
This reverts commit 9deb3c27.
The test case that was described in the associated MR (gst-plugins-good!262 (merged)) remains adequately fixed by a related MR that was merged later (gst-plugins-good!275 (merged)).
It introduced incorrect logic that broke edit lists as described in #2549 (closed)
Fixes: #2549 (closed)