Fix typo in overscroll-behavior.html WPT.

Differential Revision: https://phabricator.services.mozilla.com/D177097

bugzilla-url: https://bugzilla.mozilla.org/show_bug.cgi?id=1790138
gecko-commit: 3b489f4e43c1a368c3747e55f1490b464f7fbde0
gecko-reviewers: hiro
diff --git a/css/css-overscroll-behavior/overscroll-behavior.html b/css/css-overscroll-behavior/overscroll-behavior.html
index 0bf335d..dcd981e 100644
--- a/css/css-overscroll-behavior/overscroll-behavior.html
+++ b/css/css-overscroll-behavior/overscroll-behavior.html
@@ -119,7 +119,7 @@
   instruction3.style.fontWeight = 'bold';
   test.step(function() {
     assert_equals(root.scrollTop, 0, "overscroll-behavior-x: none should only prevent scroll propagation on x axis.");
-    assert_equalhhs(root.scrollLeft, 100, "overscroll-behavior-x: none should prevent scroll propagation on x axis." );
+    assert_equals(root.scrollLeft, 100, "overscroll-behavior-x: none should prevent scroll propagation on x axis." );
   });
 
   container.style.overscrollBehaviorX = 'none';