tests: info: add test case to reproduce infinite loop
tests: info: add test case to reproduce infinite loop

gst_debug_unset_threshold_for_name() used to go into an
infinite loop when there was more than one category in
the list.  This test captures the problem by failing
via timeout.

https://bugzilla.gnome.org/show_bug.cgi?id=748321

krichter722/gstreamer,centricular/gstreamer,mparis/gstreamer,StreamUtils/gstreamer,krichter722/gstreamer,centricular/gstreamer,mparis/gstreamer,krichter722/gstreamer,shelsonjava/gstreamer,centricular/gstreamer,jpxiong/gstreamer,StreamUtils/gstreamer,shelsonjava/gstreamer,shelsonjava/gstreamer,centricular/gstreamer,jpxiong/gstreamer,StreamUtils/gstreamer,jpxiong/gstreamer,mparis/gstreamer,jpxiong/gstreamer,krichter722/gstreamer,StreamUtils/gstreamer,centricular/gstreamer,mparis/gstreamer,shelsonjava/gstreamer,shelsonjava/gstreamer,krichter722/gstreamer,mparis/gstreamer,StreamUtils/gstreamer,jpxiong/gstreamer