Do not allow Display#getRealMetrics to return values reflecting

the app bounds.

Fixes Display#getRealMetrics sandboxing bug, where a non-null
configuration results in DisplayInfo ignoring max bounds width
and height for app bounds. Consistent with non-sandboxing
implementation of Display#getRealMetrics

Bug: 182377479
Test: atest FrameworksMockingCoreTests:android.view.DisplayTests
Change-Id: I067aeb020e1ca214aa269182c475b4553de0eb09