Refactor and reorganize type inference classes before porting ConcreteTypesInferrer to InferrerVisi…

tests/compiler/dart2js/cpa_inference_test.dart

 // Copyright (c) 2012, 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 "package:expect/expect.dart";
-import '../../../sdk/lib/_internal/compiler/implementation/scanner/scannerlib.dart';
 import '../../../sdk/lib/_internal/compiler/implementation/source_file.dart';
 import '../../../sdk/lib/_internal/compiler/implementation/types/types.dart';
+import '../../../sdk/lib/_internal/compiler/implementation/types/concrete_types_inferrer.dart';
 
 import "parser_helper.dart";
 import "compiler_helper.dart";
 
 /**
  * Finds the node corresponding to the last occurence of the substring
  * [: identifier; :] in the program represented by the visited AST.
  */
 class VariableFinderVisitor extends Visitor {
   final String identifier;
@@ skipping 1614 matching lines @@
   testJsCallAugmentsSeenClasses();
   testIsCheck();
   testSeenClasses();
   testIntDoubleNum();
   testConcreteTypeToTypeMask();
   testSelectors();
   testMixins();
   testClosures();
   testNestedFunctions();
 }