Speed up StreamingEngine unit tests
Speed up StreamingEngine unit tests

This speeds up tests on browsers other than Edge and fixes timeouts
on Safari.

Change-Id: Iea45ebc6d8bb4a3e12f738700ae2dcf2356efe5d

tvoli/shaka-player,russitto/shaka-player,baconz/shaka-player,baconz/shaka-player,TheModMaker/shaka-player,Ross-cz/shaka-player,TheModMaker/shaka-player,ustudio/shaka-player,shaka-project/shaka-player,vimond/shaka-player,brightcove/shaka-player,TobbeEdgeware/shaka-player,brightcove/shaka-player,shaka-project/shaka-player,Ross-cz/shaka-player,russitto/shaka-player,indiereign/shaka-player,brightcove/shaka-player,tvoli/shaka-player,TheModMaker/shaka-player,ustudio/shaka-player,ustudio/shaka-player,TobbeEdgeware/shaka-player,vimond/shaka-player,TobbeEdgeware/shaka-player,tvoli/shaka-player,indiereign/shaka-player,TheModMaker/shaka-player,indiereign/shaka-player,ustudio/shaka-player,shaka-project/shaka-player,shaka-project/shaka-player,russitto/shaka-player,Ross-cz/shaka-player,tvoli/shaka-player,baconz/shaka-player,vimond/shaka-player