Killsquad sends a MESessionClose at various times depending on user input. It always expects a MESessionClosed event and will wait indefinitely if not received. There are currently a number of scenarios where we don't report the MESessionClose event. This MR attempts to fix that.
-- v5: mf: Handle an error during Media Session Close. mf: Handle MediaSession Close when state is SESSION_STATE_RESTARTING_SOURCES. mf/tests: Add additional tests for MESessionClosed event.