Fix incorrect launcher loading.

Apps that were installed and downloading incrementally would be shown as fully downloaded on reboot. Updated LoaderTask and AppInfo.updateRuntimeFlagsForActivityTarget to account for this.

Fixes: 178528867

Test: manual with hardcoded values

Change-Id: I088e43ae886b4157bad9f4fa8d40373cf7f8235a
(cherry picked from commit 6d0fec8a)