Removing Launcher activity dependency on various animations

(This cl reverts change-Id: I455edcd17bda83ab51c2c04fa40e66097a4d6975)

Various animations were marked for cancellation when launcher activity is
destroyed. This this does not work with multiple activities (Launcher,
fallback recents, shortcut confirmation). Also since launcher activity
handles configuration changes, the activity is not destroyed often.

Instead associating a target with various animations which automatically
cancels the animations when that target goes away.

Change-Id: I64cd095a28075561a9e20c9dcdeb9f90c18e1047