Added antipatterns.BadViewStructureCreationSignInActivity activity.

This is a simple login page where the view structure is created onStart()
instead of onCreate(), which causes autofill to misbehave when the autofill
service requires authentication.

Bug: 114236837
Bug: 111644535

Test: ./gradlew :Application:installDebug
Test: manual verification

Change-Id: I8761a3f71ceec44aefd7378da3329643ef015ce4