HALO: halo can save last position now

Change-Id: I5a608b02323ab9fdfa3922a3c9844e75c3a1ab09

fix

Change-Id: I00ced429cfcc90507b8cc14b228a74b8902e67e8

Conflicts:
	packages/SystemUI/src/com/android/systemui/statusbar/halo/Halo.java
Revert removing FLAG_ACTIVITY_CLEAR_TOP from intent
Removing that flag from the intent provokes some apps not being able to finish pressing the back key.
This change doesn't affect other opened apps.

Change-Id: I81a47f8e648114d8e2144a3b9854ede299d67871

Conflicts:
	services/java/com/android/server/am/ActivityRecord.java