Apply split-screen resize on sync queue

This keeps it synchronized with dismissal and thus avoids
a race between pending and sync transaction application

Bug: 170801863
Test: launch a forced-multiwindow sizecompat app in split and
      then dismiss split to that app. App should not be cropped.
Change-Id: I686605928ededcd5c5d032789fd883e17f437948
Merged-in: I4d89be443af5616174ea44e62774133e3b99597c