Remove non-policy check from autofill CTS

CTS tests can NOT rely on specific system-ui presentation
and behavior. In this case, it was relying on there being a
specifically-named window for the split divider which is a
system-ui element with no policy requirements or impact.

This CL removes the "waitForSplit" sync mechanism since it
is implemented poorly and is not needed since the test
waits for both split activities to be moved into split
state anyways.

Bug: 168068970
Test: #testSplitWindow
Change-Id: I24be5e91b8077c96c72b3521de7c3a8fb17dfd84
2 files changed