Use ActivityRecord.realActivity when comparing waiting visible

We need to compare against realActivity since that represents the actual
activity that is launched since it can and will be different in the case
of activity alias. realActivity is also what we set in ActivityStarter
when we wait for the activity to be visible.

Change-Id: I48636e83172f259ed69fb65937a83f8a7a0ad138
Fixes: 37665516
Test: am start -W -n  com.google.android.calculator/com.android.calculator2.Calculator twice