Backport of "Splitmux testsuite races" into 1.18
requested to merge tpm/gst-plugins-good:backport-mr-798-into-1.18-splitmux-testsuite-races into 1.18
Backport of !798 (merged) "Splitmux testsuite races".
Commits:
- 1316dd9c splitmuxsink: Never start a new fragment with no reference buffers
- f0c24319 splitmuxsink: Forward EOS messages from async fragments.
- 5ac4fdeb splitmuxsrc: Mark running=false on shutdown.
- 41ca3b4e splitmuxsink: Don't busy loop on a non-ready pad.
- d12fa001 splitmuxsink: Don't use the element state lock
- 35cc0df5 splitmuxsink: Change EOS catching logic.
- 81ecf076 splitmuxsrc: Fix comment in a test