Compute Aspect Ratio from App Bounds in CompatChangeTests

[1] unifies aspect ratio logic in ActivityRecord, which
results in aspect ratio constraints always being applied
to app bounds as opposed to sometimes being applied to
bounds and sometimes to app bounds. This CL updates
CompatChangeTests to always check aspect ratio on app
bounds.

[1] I174661f69dc90d57c0c966baa2360adb6a5ab8a4

Test: atest CompatChangeTests
Bug: b/182268157
Change-Id: I8fa11b492862db448f628fa2426446bb487f304c
Merged-In: I40a071399e3bc159a20ade917da4c94cace0524e