Reapply "Avoid "=== true" inside code by calling a function that does this for us."

tests/utils/src/DummyCompilerTest.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.
 
 // Smoke test of the dart2js compiler API.
 
 #import('../../../lib/compiler/compiler.dart');
 #import('dart:uri');
 
 Future<String> provider(Uri uri) {
   Completer<String> completer = new Completer<String>();
   String source;
   if (uri.scheme == "main") {
     source = "main() {}";
   } else if (uri.scheme == "lib") {
     if (uri.path.endsWith("/core.dart")) {
       source = """#library('core');
                   class Object{}
                   class bool {}
                   class num {}
                   class int {}
                   class double{}
                   class String{}
                   class Function{}
                   class List {}
                   class Closure {}
                   class Dynamic {}
-                  class Null {}""";
+                  class Null {}
+                  eqNull(a) {}
+                  eqNullB(a) {}""";
     } else {
       source = "#library('lib');";
     }
   } else {
    throw "unexpected URI $uri";
   }
   completer.complete(source);
   return completer.future;
 }
 
 void handler(Uri uri, int begin, int end, String message, bool fatal) {
   print(message);
 }
 
 main() {
   String code = compile(new Uri(scheme: 'main'), new Uri(scheme: 'lib'),
                         provider, handler).value;
   if (code === null) {
     throw 'Compilation failed';
   }
 }