If home activity is not fullscreen keep drilling.

When the home activity launches a non-fullscreen activity as part of
its own task then ensureActivitiesVisibleLocked() must continue past
the launched activity when determining activities to show and hide.
Stopping at the non-fullscreen activity leaves the fullscreen home
activity hidden.

Fixes bug 11555762.

Change-Id: I9058d8cde3a41cb7f9b1f97e5c0cb32e9b0f5af7

services/java/com/android/server/am/ActivityStack.java

@@ -1140,7 +1140,7 @@ final class ActivityStack {
                     } else if (isActivityOverHome(r)) {
                         if (DEBUG_VISBILITY) Slog.v(TAG, "Showing home: at " + r);
                         showHomeBehindStack = true;
-                        behindFullscreen = true;
+                        behindFullscreen = !isHomeStack();
                     }
                 } else {
                     if (DEBUG_VISBILITY) Slog.v(