Revert "test: Drop racy double-freeze check"

This reverts commit b8ef0328dd9a2771822be169c6ced8b8b16d9fb3.
gst-media-engine: Reset bus watch id

Signed-off-by: Jens Georg <mail@jensge.org>
simple-media-engine: Fix locking

Signed-off-by: Jens Georg <mail@jensge.org>
tests: Re-enable multi-freeze test

Signed-off-by: Jens Georg <mail@jensge.org>
i18n: Update POTFILES.skip

Signed-off-by: Jens Georg <mail@jensge.org>