Kill floating activities running in the same thread when tapping outside

This change makes all activities from the same app to be finished when we tap outside the halo window. Other apps running in different threads
(floating or not) won't be finished.

Port from here: https://github.com/ParanoidAndroid/android_frameworks_base/commit/f489f45ab2ba5dd4991c241917f7f4b0fd74b884

Change-Id: Ie6d6f46b2e23be60f991520ed480c2866fb2d0e3