Fix annotation of generic method invocations in Fasta inference tests (again).

pkg/analyzer/test/src/task/strong/front_end_inference_test.dart

 // Copyright (c) 2017, 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:async';
 import 'dart:convert';
 import 'dart:io';
 
 import 'package:analyzer/dart/ast/ast.dart';
 import 'package:analyzer/dart/ast/visitor.dart';
@@ skipping 257 matching lines @@
     if (node.typeArguments == null) {
       DartType type = node.staticType;
       if (type is InterfaceType) {
         _recordTypeArguments(node.offset, type.typeArguments);
       }
     }
   }
 
   visitMethodInvocation(MethodInvocation node) {
     super.visitMethodInvocation(node);
-    var inferredTypeArguments = _getInferredFunctionTypeArguments(
-            node.function.staticType, node.staticInvokeType, node.typeArguments)
-        .toList();
-    if (inferredTypeArguments.isNotEmpty) {
-      _recordTypeArguments(node.methodName.offset, inferredTypeArguments);
+    if (node.typeArguments == null) {
+      var inferredTypeArguments = _getInferredFunctionTypeArguments(
+              node.function.staticType,
+              node.staticInvokeType,
+              node.typeArguments)
+          .toList();
+      if (inferredTypeArguments.isNotEmpty) {
+        _recordTypeArguments(node.methodName.offset, inferredTypeArguments);
+      }
     }
   }
 
   visitSimpleIdentifier(SimpleIdentifier node) {
     super.visitSimpleIdentifier(node);
     Element element = node.staticElement;
     void recordPromotions(DartType elementType) {
       if (node.inGetterContext() && !node.inDeclarationContext()) {
         int offset = node.offset;
         DartType type = node.staticType;
@@ skipping 58 matching lines @@
 
   /// Based on DDC code generator's `_recoverTypeArguments`
   Iterable<DartType> _recoverTypeArguments(FunctionType g, FunctionType f) {
     assert(identical(g.element, f.element));
     assert(g.typeFormals.isNotEmpty && f.typeFormals.isEmpty);
     assert(g.typeFormals.length + g.typeArguments.length ==
         f.typeArguments.length);
     return f.typeArguments.skip(g.typeArguments.length);
   }
 }