Bug 1801782 - Drop a redundant pan update phase in panRightToLeft. r=botond

Differential Revision: https://phabricator.services.mozilla.com/D163181

gfx/layers/apz/test/mochitest/apz_test_native_event_utils.js

@@ -1853,14 +1853,6 @@ async function panRightToLeft(aElement, aX, aY, aMultiplier) {
     0,
     NativePanHandler.updatePhase
   );
-  await NativePanHandler.promiseNativePanEvent(
-    aElement,
-    aX,
-    aY,
-    NativePanHandler.delta * aMultiplier,
-    0,
-    NativePanHandler.updatePhase
-  );
   await NativePanHandler.promiseNativePanEvent(
     aElement,
     aX,

widget/tests/browser/browser_test_swipe_gesture.js

@@ -935,7 +935,7 @@ add_task(async () => {
   await panRightToLeft(tab.linkedBrowser, 100, 100, 1);
   // NOTE: The last endPhase shouldn't fire a wheel event since
   // its delta is zero.
-  is(wheelEventCount, 3, "Received 3 wheel events");
+  is(wheelEventCount, 2, "Received 2 wheel events");
 
   await waitForWhile();
   // Make sure any navigation didn't happen.