ApplicationLoaders: hard failures & tests

Make errors in ApplicationLoaders caching hard failures since they are
only ever expected under bad configuration. Tests for these are also
added.

Test: atest android.app.ApplicationLoadersTest
Bug: 128529256
Change-Id: Ib259bcdf472e6a2f7f6b1071bb70cfead4502231
Merged-In: Ib259bcdf472e6a2f7f6b1071bb70cfead4502231