Cache number of type arguments in class object instead of recalculating it.

runtime/vm/class_finalizer.h

 // 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.
 
 #ifndef VM_CLASS_FINALIZER_H_
 #define VM_CLASS_FINALIZER_H_
 
 #include "vm/allocation.h"
 #include "vm/growable_array.h"
 
@@ skipping 137 matching lines @@
   static void ReportMalformedType(const Error& prev_error,
                                   const Script& script,
                                   const Type& type,
                                   const char* format,
                                   va_list args);
   static void ReportError(const Error& error);
   static void ReportError(const Error& prev_error,
                           const Script& script,
                           intptr_t token_index,
                           const char* format, ...) PRINTF_ATTRIBUTE(4, 5);
-  static void ReportError(const char* format, ...) PRINTF_ATTRIBUTE(1, 2);
 
   // Verify implicit offsets recorded in the VM for direct access to fields of
   // Dart instances (e.g: _TypedListView, _ByteDataView).
   static void VerifyImplicitFieldOffsets();
 };
 
 }  // namespace dart
 
 #endif  // VM_CLASS_FINALIZER_H_