DO NOT MERGE Fix Autohide functionality

Make sure that opening the notification panel doesn't result in a "blip"
in the nav bar visibility

Bug: 147427386
Bug: 149021759
Bug: 149115608
Test: on hawk
adb shell settings put global policy_control "immersive.navigation=*"
swipe up from bottom of screen - make sure it autohides
pull down notification panel - make sure the panel doesn't blip
on sdk_gphone_x86 - atest SystemUITests

Change-Id: I4b5244e5ff26fb23e687cd46bc105d4fb8251bc6