Remove outdated logic of checking display-has-content

The method is no longer called in perform surface placement.
It won't trigger another pass by setting the pending change.

Also since I225fff1ff4f0738bdaf06f6813b53dbf26caf0a7, which can
update the display-has-content in time. So this logic become
dead code.

Bug: 163976519
Flag: EXEMPT remove dead code
Test: CtsWindowManagerDeviceActivity
Change-Id: Ic16dd5a1949a962df0e6088a8086fd0780f549b3