Make sure system UI context has the same LoadedApk as system context

When the system Application object is created, it should be shared by
both system and system UI context.

Bug: 37111478
Test: - Open settings
Test: - adb shell am crash com.android.settings
Test: - with crash dialog open, press volume keys
Test: - observe no crash
Change-Id: I2b4656680d25fe61fee69c01ee10522aac4e2942