Disable hoisting CheckClass due to excessive deoptimization.

runtime/vm/code_generator.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_CODE_GENERATOR_H_
 #define VM_CODE_GENERATOR_H_
 
 #include "vm/globals.h"
 #include "vm/runtime_entry.h"
 
@@ skipping 53 matching lines @@
   V(ShiftMintOp)                                                               \
   V(BinaryDoubleOp)                                                            \
   V(InstanceSetter)                                                            \
   V(Equality)                                                                  \
   V(RelationalOp)                                                              \
   V(EqualityClassCheck)                                                        \
   V(NoTypeFeedback)                                                            \
   V(UnaryOp)                                                                   \
   V(UnboxInteger)                                                              \
   V(CheckClass)                                                                \
+  V(HoistedCheckClass)                                                         \
   V(CheckSmi)                                                                  \
   V(CheckArrayBound)                                                           \
   V(AtCall)                                                                    \
   V(DoubleToSmi)                                                               \
   V(Int32Load)                                                                 \
   V(Uint32Load)                                                                \
   V(GuardField)                                                                \
   V(NumReasons)                                                                \
 
 enum DeoptReasonId {
@@ skipping 11 matching lines @@
 
 void DeoptimizeAt(const Code& optimized_code, uword pc);
 void DeoptimizeAll();
 
 double DartModulo(double a, double b);
 void SinCos(double arg, double* sin_res, double* cos_res);
 
 }  // namespace dart
 
 #endif  // VM_CODE_GENERATOR_H_