Fix ActivityManagerServiceTest and OomAdjustTests.

These tests were broken by ag/10618021. The changes made
to WindowProcessController run under the assumption that a
PackageManagerInternal instance is registered with LocalServices and a
non-null package name is set in the ApplicationInfo.

Fixes: 154346673

Test: ActivityManagerServiceTest
Test: OomAdjusterTests
Change-Id: I4cbf04e105e2db68c8766b8ed84ea5fa41fcab7a