[isolate] Remove unused exception handle

src/js/promise.js

Index: src/js/promise.js
diff --git a/src/js/promise.js b/src/js/promise.js
index a666080e78654b0474a48badc009058a416ab39c..463fc25e00effc521f1a212f56e6b00d19d4022d 100644
--- a/src/js/promise.js
+++ b/src/js/promise.js
@@ -12,6 +12,7 @@
 // Imports
 
 var InternalArray = utils.InternalArray;
+var MicrotaskEnq;
 var promiseCombinedDeferredSymbol =
     utils.ImportNow("promise_combined_deferred_symbol");
 var promiseHasHandlerSymbol =
@@ -31,6 +32,7 @@ var toStringTagSymbol = utils.ImportNow("to_string_tag_symbol");
 
 utils.Import(function(from) {
   SpeciesConstructor = from.SpeciesConstructor;
+  MicrotaskEnq = from.MicrotaskEnq;
 });
 
 // -------------------------------------------------------------------
@@ -166,7 +168,7 @@ function PromiseHandle(value, handler, deferred) {
 
 function PromiseEnqueue(value, tasks, deferreds, status) {
   var id, name, instrumenting = DEBUG_IS_ACTIVE;
-  %EnqueueMicrotask(function() {
+  MicrotaskEnq(function() {
     if (instrumenting) {
       %DebugAsyncTaskEvent({ type: "willHandle", id: id, name: name });
     }
@@ -279,7 +281,7 @@ function ResolvePromise(promise, resolution) {
       var id;
       var name = "PromiseResolveThenableJob";
       var instrumenting = DEBUG_IS_ACTIVE;
-      %EnqueueMicrotask(function() {
+      MicrotaskEnq(function() {
         if (instrumenting) {
           %DebugAsyncTaskEvent({ type: "willHandle", id: id, name: name });
         }