Cleanup references to the old DDC repo

pkg/dev_compiler/tool/input_sdk/private/ddc_runtime/operations.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.
 
 /// This library defines runtime operations on objects used by the code
 /// generator.
 part of dart._runtime;
 
 class InvocationImpl extends Invocation {
   final Symbol memberName;
@@ skipping 743 matching lines @@
   var extension = getExtensionType(obj);
   if (extension != null) {
     return JS('String', '#[dartx.toString]()', obj);
   }
   if (JS('bool', 'typeof # == "function"', obj)) {
     return JS(
         'String', r'"Closure: " + # + " from: " + #', getReifiedType(obj), obj);
   }
   // TODO(jmesserly): restore this faster path once ES Symbol is treated as
   // an extension type (and thus hits the above code path).
-  // See https://github.com/dart-lang/dev_compiler/issues/578.
+  // See https://github.com/dart-lang/sdk/issues/28323
   // return JS('', '"" + #', obj);
   return JS('String', '#.toString()', obj);
 }
 
 // TODO(jmesserly): is the argument type verified statically?
 noSuchMethod(obj, Invocation invocation) {
   if (obj == null || JS('bool', 'typeof # == "function"', obj)) {
     throw new NoSuchMethodError(obj, invocation.memberName,
         invocation.positionalArguments, invocation.namedArguments);
   }
@@ skipping 66 matching lines @@
     name = '+' + name;
   }
   return name;
 }
 
 /// Emulates the implicit "loadLibrary" function provided by a deferred library.
 ///
 /// Libraries are not actually deferred in DDC, so this just returns a future
 /// that completes immediately.
 Future loadLibrary() => new Future.value();