Pausing the resumed activity when making it invisible

A resumed activity was added to stopping activity lists while
making it invisible without having state changes. So, the
activity won't be resumed if it becomes visible again because
the activity is already in the resumed state.

mSetToSleep was used in 9b8ece20, which wasn't a reliable way to
determine if the activity is resuming because it gets updates until
set to sleep. Now we use Task#mInResumeTopActivity instead.

Bug: 160435184
Test: atest ActivityRecordTests
Change-Id: I3509ba75e3f2d87c863d52c0fb07d69cbfe41764