Check if APK paths are valid right before creating the context.

The check has to be done in RemoteViews and in AppWidgetHostView right
before creating the context used to inflate the app widget. Further, the
APK is cached potentially in two places: in the APK with code and the
APK without codes, so both places are updated if present.

Test: manual, see bug for details
Fix: 202369942

Change-Id: I5718f67711a3332a942d3c037eef7f30379549a4