implement `Invocation.typeArguments` in DDC

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

Index: pkg/dev_compiler/tool/input_sdk/patch/internal_patch.dart
diff --git a/pkg/dev_compiler/tool/input_sdk/patch/internal_patch.dart b/pkg/dev_compiler/tool/input_sdk/patch/internal_patch.dart
index 30f35ac42df08ffcc21d5c504013119f4bc462ca..d57a1f092a12162cfdc26bbcb08477ea0eaf6e74 100644
--- a/pkg/dev_compiler/tool/input_sdk/patch/internal_patch.dart
+++ b/pkg/dev_compiler/tool/input_sdk/patch/internal_patch.dart
@@ -43,7 +43,11 @@ class PrivateSymbol implements core.Symbol {
   }
 
   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")';