ios: Fix CRWTouchTrackingRecognizer state machine cancel error.

Bug: 1081716
Change-Id: I48aa648d4ee6fc38e5fba36689814431e2cb56be
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2238463Reviewed-by: Eugene But <eugenebut@chromium.org>
Reviewed-by: Gauthier Ambard <gambard@chromium.org>
Commit-Queue: Justin Cohen <justincohen@chromium.org>
Cr-Commit-Position: refs/heads/master@{#776933}

ios/web/web_state/ui/crw_touch_tracking_recognizer.mm

@@ -46,6 +46,7 @@
 
 - (void)touchesCancelled:(NSSet*)touches withEvent:(UIEvent*)event {
   [super touchesCancelled:touches withEvent:event];
+  self.state = UIGestureRecognizerStateCancelled;
   [self.touchTrackingDelegate touched:NO];
 }