Fix PackageSetting uses-static-library and add adoptable storage tests

Reading <uses-static-library/> was broken since its introduction. This
updates the Settings code and adds a test case.

Also adds tests to generally verify adoptable storage ejection cases
where an app is moved to an SD card and unmounted, making the APK file
unavailable.

Bug: 145992607

Test: atest com.android.server.pm.PackageManagerSettingsTests
Test: atest com.android.server.pm.test.SdCardEjectionTests

Change-Id: Ia997f8e901eb2730fa3ecd923dc6fe6563a7781b