meson: Enable libs_video unit test

It does not timeout anymore, even though it's a very slow test. For the
context, this test runs routines for a fixes amount of time and prints
the throughput. Which means the test takes more time everytime a pixel
format is added. If that becomes a problem again, we should disable the
benchmarks by default.

tests/check/meson.build

@@ -23,7 +23,7 @@ base_tests = [
   [ 'libs/rtspconnection.c' ],
   [ 'libs/sdp.c' ],
   [ 'libs/tag.c' ],
-  #  [ 'libs/video' ], # FIXME: times out, perhaps split or spawn conversions into benchmark tool and/or multiple threads
+  [ 'libs/video.c' ],
   [ 'libs/videoencoder.c' ],
   [ 'libs/videotimecode.c' ],
   [ 'libs/xmpwriter.c' ],