Make it easier to profile thumbnailers

Bastien Nocera requested to merge wip/hadess/thumbnail-test-stats into master

Run 3 iterations of the thumbnailer, and print how long the first iteration took, vs. the average of the others:

$ ./test-desktop-thumbnail -n 3 -t ~/Videos/bbb_sunflower_1080p_60fps_normal.mp4 foo.png 
First iteration: 178 msec
Average time: 171 msec (2 iterations)
Edited by Bastien Nocera

Merge request reports