Fix the broken unit tests

PhoneAccountRegistrarTest is broken, and also non-functional. Get them
updated by fixing proguard (don't strip @VisibleForTesting things),
fixing the setup (need a real ConnectionService), and fixing the tests
themselves to test what PhoneAccountRegistrar does now.

Bug: 17620636
Change-Id: Ibd4d5a4104ff2158b0e7c01a41910f866b94196a
diff --git a/proguard.flags b/proguard.flags
new file mode 100644
index 0000000..e52ac20
--- /dev/null
+++ b/proguard.flags
@@ -0,0 +1,4 @@
+-verbose
+
+# Keep @VisibleForTesting elements
+-keep @com.android.internal.annotations.VisibleForTesting class *