implement `Invocation.typeArguments` in DDC

pkg/dev_compiler/tool/input_sdk/patch/internal_patch.dart

 // Copyright (c) 2013, 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.
 
 import 'dart:_js_primitives' show printString;
 import 'dart:_js_helper' show patch;
 import 'dart:_interceptors' show JSArray;
 import 'dart:_foreign_helper' show JS;
 
 @patch
@@ skipping 25 matching lines @@
   const PrivateSymbol(this._name, this._nativeSymbol);
 
   static String getName(core.Symbol symbol) => (symbol as PrivateSymbol)._name;
 
   static Object getNativeSymbol(core.Symbol symbol) {
     if (symbol is PrivateSymbol) return symbol._nativeSymbol;
     return null;
   }
 
   bool operator ==(other) =>
-      other is PrivateSymbol && identical(_nativeSymbol, other._nativeSymbol);
+      other is PrivateSymbol &&
+      _name == other._name &&
+      identical(_nativeSymbol, other._nativeSymbol);
+
+  get hashCode => _nativeSymbol.hashCode;
 
   // TODO(jmesserly): is this equivalent to _nativeSymbol toString?
   toString() => 'Symbol("$_name")';
 }
 
 @patch
 void printToConsole(String line) {
   printString('$line');
 }
 
 @patch
 List/*<E>*/ makeListFixedLength/*<E>*/(List/*<E>*/ growableList) {
   JSArray.markFixedList(growableList);
   return growableList;
 }
 
 @patch
 List/*<E>*/ makeFixedListUnmodifiable/*<E>*/(List/*<E>*/ fixedLengthList) {
   JSArray.markUnmodifiableList(fixedLengthList);
   return fixedLengthList;
 }