fix #30094, assert should work with a function

pkg/dev_compiler/tool/input_sdk/private/ddc_runtime/errors.dart

 // Copyright (c) 2015, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 part of dart._runtime;
 
 // We need to set these properties while the sdk is only partially initialized
 // so we cannot use regular Dart fields.
 // The default values for these properties are set when the global_ final field
 // in runtime.dart is initialized.
 
@@ skipping 55 matching lines @@
   var expected = typeName(type);
   if (JS('bool', 'dart.__trapRuntimeErrors')) JS('', 'debugger');
   throw new StrongModeTypeError(object, found, expected);
 }
 
 throwUnimplementedError(String message) {
   if (JS('bool', 'dart.__trapRuntimeErrors')) JS('', 'debugger');
   throw new UnimplementedError(message);
 }
 
-throwAssertionError([String message()]) {
+throwAssertionError(messageFn()) {
   if (JS('bool', 'dart.__trapRuntimeErrors')) JS('', 'debugger');
-  throw message != null
-      ? new AssertionErrorWithMessage(message())
-      : new AssertionError();
+  var message = messageFn != null ? messageFn() : null;
+  throw new AssertionErrorImpl(message);
 }
 
 throwCyclicInitializationError([String message]) {
   if (JS('bool', 'dart.__trapRuntimeErrors')) JS('', 'debugger');
   throw new CyclicInitializationError(message);
 }
 
 throwNullValueError() {
   // TODO(vsm): Per spec, we should throw an NSM here.  Technically, we ought
   // to thread through method info, but that uglifies the code and can't
   // actually be queried ... it only affects how the error is printed.
   if (JS('bool', 'dart.__trapRuntimeErrors')) JS('', 'debugger');
   throw new NoSuchMethodError(
       null, new Symbol('<Unexpected Null Value>'), null, null, null);
 }
 
 throwNoSuchMethodError(Object receiver, Symbol memberName,
     List positionalArguments, Map<Symbol, dynamic> namedArguments) {
   if (JS('bool', 'dart.__trapRuntimeErrors')) JS('', 'debugger');
   throw new NoSuchMethodError(
       receiver, memberName, positionalArguments, namedArguments);
 }