Make the safe Console singleton be const

tools/dom/templates/html/dart2js/impl_Console.darttemplate

 // Copyright (c) 2012, 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 $LIBRARYNAME;
 
 $(ANNOTATIONS)$(CLASS_MODIFIERS)class Console {
 
-  Console._safe() {}
+  const Console._safe();
 
-  static Console _safeConsole = new Console._safe();
+  static const Console _safeConsole = const Console._safe();
 
   bool get _isConsoleDefined => JS('bool', 'typeof console != "undefined"');
 
   @DomName('Console.memory')
   MemoryInfo get memory => _isConsoleDefined ?
       JS('MemoryInfo', 'console.memory') : null;
 
   @DomName('Console.assertCondition')
   void assertCondition(bool condition, Object arg) => _isConsoleDefined ?
       JS('void', 'console.assertCondition(#, #)', condition, arg) : null;
 
   @DomName('Console.clear')
   void clear(Object arg) => _isConsoleDefined ?
       JS('void', 'console.clear(#)', arg) : null;
 
   @DomName('Console.count')
   void count(Object arg) => _isConsoleDefined ?
       JS('void', 'console.count(#)', arg) : null;
 
   @DomName('Console.debug')
   void debug(Object arg) => _isConsoleDefined ?
       JS('void', 'console.debug(#)', arg) : null;
 
   @DomName('Console.dir')
   void dir(Object arg) => _isConsoleDefined ?
-      JS('void', 'console.debug(#)', arg) : null;
+      JS('void', 'console.dir(#)', arg) : null;
 
   @DomName('Console.dirxml')
   void dirxml(Object arg) => _isConsoleDefined ?
       JS('void', 'console.dirxml(#)', arg) : null;
 
   @DomName('Console.error')
   void error(Object arg) => _isConsoleDefined ?
       JS('void', 'console.error(#)', arg) : null;
 
   @DomName('Console.group')
@@ skipping 46 matching lines @@
 
   @DomName('Console.trace')
   void trace(Object arg) => _isConsoleDefined ?
       JS('void', 'console.trace(#)', arg) : null;
 
   @DomName('Console.warn')
   void warn(Object arg) => _isConsoleDefined ?
       JS('void', 'console.warn(#)', arg) : null;
 $!MEMBERS
 }