Sandbox letterbox and size compat apps

Sandbox Display#getRealSize and WindowManager
bounds when letterbox or size compat mode are
applied to the configuration. Display uses
this field to provide the sandboxed display
size.

This reverts commit 0ba61856.

Test: atest WindowConfigurationTests
Test: atest FrameworksMockingCoreTests:android.view.DisplayTests
Test: atest WmTests:SizeCompatTests
Bug: 181219241

Change-Id: I86e8edb8368269da8e02cf34f429d245550666c6