Workaround launching PiP task with CLEAR_TASK & NEW_TASK flag.

- When launching an activity with CLEAR_TASK and NEW_TASK, the result code
  of the start is START_SUCCESS, but we still need to notify SystemUI to
  expand the PiP.  However, because the PiP transition now waits for the
  first draw, this can cause severe jank and delay if the original activity
  is a trampoline activity. As a workaround, we immediately move the task
  to the fullscreen stack when clearing and restarting the task to ensure
  that the new task shows without delay.

Bug: 37501224
Test: Open YT in PIP, launch sub-shortcut from Home

Change-Id: I16bebf19b082f30695e99da1d93bc4adf5e9df0c