Fix JS syntax error on wpt/service-workers/.../fetch-event.https.html

This is a reland of https://crrev.com/c/2704748.

Bug: 1165690
Change-Id: Ifedbdf846fb01cb43e0cfd61085df957ee58b036
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2706929
Commit-Queue: Yutaka Hirano <yhirano@chromium.org>
Commit-Queue: Adam Rice <ricea@chromium.org>
Auto-Submit: Yutaka Hirano <yhirano@chromium.org>
Reviewed-by: Adam Rice <ricea@chromium.org>
Cr-Commit-Position: refs/heads/master@{#855699}
diff --git a/service-workers/service-worker/fetch-event.https.html b/service-workers/service-worker/fetch-event.https.html
index cdd24c5..4c79670 100644
--- a/service-workers/service-worker/fetch-event.https.html
+++ b/service-workers/service-worker/fetch-event.https.html
@@ -553,7 +553,7 @@
     await promise_rejects_js(t, TypeError, frame.contentWindow.fetch(echo_url, {
         method: 'POST',
         body: rs
-    });
+    }));
   }, 'FetchEvent#body is a ReadableStream, used and passed to network fallback');
 
 // Test that the request body is sent to network upon network fallback even when