[async await] Fix debug async task event

src/js/async-await.js

 // Copyright 2016 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 (function(global, utils, extrasUtils) {
 
 "use strict";
 
 %CheckIsBootstrapping();
 
@@ skipping 140 matching lines @@
       name: "async function",
     });
   }
   return promise;
 }
 
 function AsyncFunctionPromiseRelease(promise) {
   if (DEBUG_IS_ACTIVE) {
     // Cancel
     var id = GET_PRIVATE(promise, promiseAsyncStackIDSymbol);
-    %DebugAsyncTaskEvent({
-      type: "cancel",
-      id: id,
-      name: "async function",
-    });
+
+    // Don't send invalid events when catch prediction is turned on in
+    // the middle of some async operation.
+    if (!IS_UNDEFINED(id)) {
+      %DebugAsyncTaskEvent({
+        type: "cancel",
+        id: id,
+        name: "async function",
+      });
+    }
     // Pop the Promise under construction in an async function on
     // from catch prediction stack.
     %DebugPopPromise();
   }
 }
 
 %InstallToContext([
   "async_function_await_caught", AsyncFunctionAwaitCaught,
   "async_function_await_uncaught", AsyncFunctionAwaitUncaught,
   "reject_promise_no_debug_event", RejectPromiseNoDebugEvent,
   "async_function_promise_create", AsyncFunctionPromiseCreate,
   "async_function_promise_release", AsyncFunctionPromiseRelease,
 ]);
 
 })