[isolate] Remove unused exception handle

src/js/microtaskq.js

+// Copyright 2012 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();
+
+  // ----------------------------------------------------------
+  // Imports
+
+  let InternalArray = utils.InternalArray;
+
+  // -------------------------------------------------------------------
+
+  let microtaskQ = []
+
+  function MicrotaskEnq(task) {
+    microtaskQ.push(task);
+  }
+
+  function MicrotaskRun() {
+    for( var i = 0; i < microtaskQ.length; i ++) {
+      try {
+        microtaskQ[i]();
+      } catch (e) {}
+    }
+
+    microtaskQ = [];
+  }
+
+  // -------------------------------------------------------------------
+  // Install exported functions.
+
+  utils.Export(function(to) {
+    to.MicrotaskEnq = MicrotaskEnq;
+  });
+
+  %InstallToContext([
+    "microtask_run", MicrotaskRun,
+    "microtask_enq", MicrotaskEnq
+  ]);
+})