Mirror API for IsAsyncFunction

test/mjsunit/mirror-function-async.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.
+
+// Flags: --expose-debug-as debug --harmony-async-await
+
+async function foo() {}
+function bar() {}
+
+let fooMirror = debug.MakeMirror(foo);
+assertTrue(fooMirror.isAsyncFunction());
+
+let barMirror = debug.MakeMirror(bar);
+assertFalse(barMirror.isAsyncFunction());