Add BEHAVIOR_DEFAULT for visual immersive mode

BEHAVIOR_DEFAULT lets the user can use single gesture to navigate while
system bars are hidden in gesture navigation mode. The user doesn't
need to make navigation bar visible before performing navigation.

BEHAVIOR_DEFAULT will be the default behavior, which means if there is
no system bar behavior (or any legacy sysui flag about immersive)
specified, the behavior will be BEHAVIOR_DEFAULT instead of
BEHAVIOR_SHOW_BARS_BY_TOUCH.

BEHAVIOR_SHOW_BARS_BY_TOUCH and BEHAVIOR_SHOW_BARS_BY_SWIPE are
deprecated. Their behavior is equivalent to BEHAVIOR_DEFAULT now. The
logic about HideNavInputEventReceiver is removed.

Bug: 168913586
Test: atest WindowInsetsControllerTests ViewRootImplTest
            DisplayPolicyTests CommandQueueTest
            LightsOutNotifControllerTest RegisterStatusBarResultTest
Change-Id: Ic818e323abbb38b57bef9fc36fb1afef2a007f1b