fix metrics density comparisons

In Resources.java, we explicitly call setDensity() on the local
DisplayMetircs object when there is a configuration update - which
sets some more fields than the original implementation.

In fw/b/core/java/android/app/Presentation.java there is a DisplayInfo
comparison which fails because our getMetricsWithSize() did not always
set those fields that updateConfiguration would always set.

So now we always return a DisplayMetrics object with the fields filled
out as expected.

Ref: OPO-539

Change-Id: Ie80e7a9cfd249ec59d31b4044ad09e07e34d1194
Signed-off-by: Roman Birg <roman@cyngn.com>