Make header include guards great again

runtime/vm/unit_test.h

 // Copyright (c) 2011, 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.
 
-#ifndef VM_UNIT_TEST_H_
-#define VM_UNIT_TEST_H_
+#ifndef RUNTIME_VM_UNIT_TEST_H_
+#define RUNTIME_VM_UNIT_TEST_H_
 
 #include "include/dart_native_api.h"
 
 #include "platform/globals.h"
 
 #include "vm/ast.h"
 #include "vm/dart.h"
 #include "vm/globals.h"
 #include "vm/heap.h"
 #include "vm/isolate.h"
@@ skipping 595 matching lines @@
     *flag_ = original_value_;
   }
 
  private:
   T* flag_;
   T original_value_;
 };
 
 }  // namespace dart
 
-#endif  // VM_UNIT_TEST_H_
+#endif  // RUNTIME_VM_UNIT_TEST_H_