Wait for next app to be visible if current activity is marked visible

WM's AppWindowToken.updateReportedVisibilityLocked() may not report
nowVisible if the app has animation set. So nowVisibible could be false
for a while after the app is already on screen. If we finish the app in
this state, we still need to wait for next app to be visible.

bug: 28019637
Change-Id: I4f9f8e138f5d011a9ab393913159ed2978d26e0d