[ATMS] Remove some dead code from Task

There isn't any task that's in fullscreen mode and not organized. This
CL also removed a relevant test.

Bug: 228939973
Test: Prebuild tests.
Test: atest TaskTests#testFullscreenBoundsForcedOrientation
Change-Id: I9be0fece29fc18782909d75b32b1688ca0f3b34d