Revert "Enable type inference when using mirrors."

tests/compiler/dart2js_extra/mirror_type_inference_field_test.dart

Index: tests/compiler/dart2js_extra/mirror_type_inference_field_test.dart
diff --git a/tests/compiler/dart2js_extra/mirror_type_inference_field_test.dart b/tests/compiler/dart2js_extra/mirror_type_inference_field_test.dart
deleted file mode 100644
index 860d8c76ec8ed8aa16e4332636cfc2ab5fd00da9..0000000000000000000000000000000000000000
--- a/tests/compiler/dart2js_extra/mirror_type_inference_field_test.dart
+++ /dev/null
@@ -1,20 +0,0 @@
-// Copyright (c) 2013, 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.
-
-// Test that type inference sees the possible modification of `fisk` from
-// the mirror system and not infers the value to be an integer.
-library test;
-
-@MirrorsUsed(targets: 'fisk', override: '*')
-import 'dart:mirrors';
-
-import 'package:expect/expect.dart';
-
-var fisk = 1;
-
-main() {
-  var lm = currentMirrorSystem().findLibrary(const Symbol('test')).single;
-  lm.setField(const Symbol('fisk'), 'hest');
-  Expect.isTrue(fisk is String);
-}