Attach the Display KeyStateTracker to body, don't update in PDOMPoint…

…er, see #1048

js/display/Display.js

@@ -1902,6 +1902,7 @@ Display.userGestureEmitter = new Emitter();
 // @public (read-only) {KeyStateTracker} - A global object that tracks the state of the keyboard for all Displays. Use this
 // to get information about which keyboard keys are pressed down and for how long.
 Display.keyStateTracker = new KeyStateTracker();
+Display.keyStateTracker.attachToBody();
 
 /**
  * Returns true when NO nodes in the subtree are disposed.

js/input/PDOMPointer.js

@@ -66,7 +66,6 @@ class PDOMPointer extends Pointer {
         if ( this.blockTrustedEvents && event.domEvent.isTrusted ) {
           return;
         }
-        Display.keyStateTracker.keydownUpdate( event.domEvent );
 
         // set the target to potentially block keyup events
         this.keydownTargetNode = event.target;
@@ -75,7 +74,6 @@ class PDOMPointer extends Pointer {
         if ( this.blockTrustedEvents && event.domEvent.isTrusted ) {
           return;
         }
-        Display.keyStateTracker.keyupUpdate( event.domEvent );
 
         // The keyup event was received on a node that didn't receive a keydown event, abort to prevent any other
         // listeners from being called for this event. Done after updating KeyStateTracker so that the global state