Never resume activities that are partially occluded

Activities should not be resumed if they are partially occluded by
transparent activities on top. The existing checks did not take into
account other transparent stacks.

Bug: 123937780
Bug: 123991542
Test: atest WmTests:ActivityRecordTests#testShouldResume_stackVisibility
Test: atest WmTests:ActivityStackTests
Test: Launch Calendar, press HOME, launch Calendar again.
Test: go/wm-smoke
Change-Id: I7e4dfeeb72144e7c71e3d53c595c8ac632ad4027