plugins: *queue* elements: Handle STREAM_START in EOS situation

plugins: *queue* elements: Handle STREAM_START in EOS situation

When queue-like elements are in "EOS" situation (received GST_FLOW_EOS
from downstream or EOS was pushed), they drain buffers/events that
wouldn't be processed anyway and let through events that might
modify the EOS situation.

Previously only GST_EVENT_EOS and GST_EVENT_SEGMENT events were let
through, but we also need to allow GST_EVENT_STREAM_START to go
through since it resets the EOS state of pads since 1.6

https://bugzilla.gnome.org/show_bug.cgi?id=786034