Revert "Convert Keyguard tests to Robolectric tests" am: 122768bf80

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/21340156

Change-Id: Ia88283e584622308e003cf20a825dc2ec2aedcfe
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>