Updated tests/compiler/* to use new library syntax.

tests/compiler/dart2js/is_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("compiler_helper.dart");
+import 'compiler_helper.dart';
 
 const String TEST_IF = r"""
 test(param) {
   if (param is int) {
     param = param + 42;
   }
   return param + 53;
 }
 """;
 
@@ skipping 56 matching lines @@
 }
 
 main() {
   compileAndTest(TEST_IF);
   compileAndTest(TEST_IF_ELSE);
   compileAndTest(TEST_IF_RETURN);
   compileAndTest(TEST_IF_NOT_ELSE);
   compileAndTest(TEST_IF_NOT_RETURN);
   compileAndTest(TEST_IF_NOT_ELSE_RETURN);
 }