Make FASS accessible from winscope

Flickerlib has been refactored so that more functionality can be used directly in Winscope.

This will enable us to add an option in winscope to detect transitions for manually
created WM and SF traces, without relying on flicker.

The winscope change is not part of this topic.

This CL updates the tests to reflect this change

Test: atest FlickerTests WMShellFlickerTests
Change-Id: I767e8993b5565af5fdb82eba53fabf8afb865b6e