Fix annotation of generic method invocations in Fasta inference tests.

pkg/front_end/testcases/inference/generic_methods_nested_generic_instantiation.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.
 
 /*@testedFeatures=inference*/
 library test;
 
 import 'dart:math' as math;
 
 class Trace {
   List<Frame> frames = /*@typeArgs=Frame*/ [];
 }
 
 class Frame {
   String location = '';
 }
 
 main() {
   List<Trace> traces = /*@typeArgs=Trace*/ [];
   var /*@type=int*/ longest = /*@promotedType=none*/ traces
-      .map(/*@returnType=int*/ (/*@type=Trace*/ trace) {
+      . /*@typeArgs=int*/ map(/*@returnType=int*/ (/*@type=Trace*/ trace) {
     return /*@promotedType=none*/ trace.frames
-        .map(/*@returnType=int*/ (/*@type=Frame*/ frame) =>
+        . /*@typeArgs=int*/ map(/*@returnType=int*/ (/*@type=Frame*/ frame) =>
             /*@promotedType=none*/ frame.location.length)
-        .fold(0, math.max);
-  }).fold(0, math.max);
+        . /*@typeArgs=int*/ fold(0, math.max);
+  }). /*@typeArgs=int*/ fold(0, math.max);
 }