Set start time for open folder animation before starting the animation

The start time of the animation was being set after the animation started
causing the animation to jump to an start time after it already
started wich was very obvious when setting the animation speed to 0.

To test set the aimation speed to zero like so:

  adb shell settings put global animator_duration_scale 0
  adb shell settings put global transition_animation_scale 0
  adb shell settings put global window_animation_scale 0

Fix: 279662507
Test: explained above
Test: FolderScreenShootTest will test it in the future
Change-Id: Id6e10720ffdf64e062e533cd3187f386f57ae906