Revert "rtpjitterbuffer: Avoid deadlock on flush"
Revert "rtpjitterbuffer: Avoid deadlock on flush"

This reverts commit 54810bf44f27d9c180730f58f16f6e172c7b0bc8

Part-of: <https://gitlab.freedesktop.org/gstreamer/gst-plugins-good/-/merge_requests/620>

GStreamer/gst-plugins-good,pexip/gst-plugins-good,pexip/gst-plugins-good,GStreamer/gst-plugins-good,pexip/gst-plugins-good,GStreamer/gst-plugins-good,pexip/gst-plugins-good,pexip/gst-plugins-good,GStreamer/gst-plugins-good