[interpreter] Add support for scalable operands.

src/interpreter/constant-array-builder.h

 // Copyright 2015 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef V8_INTERPRETER_CONSTANT_ARRAY_BUILDER_H_
 #define V8_INTERPRETER_CONSTANT_ARRAY_BUILDER_H_
 
 #include "src/identity-map.h"
 #include "src/interpreter/bytecodes.h"
 #include "src/zone-containers.h"
@@ skipping 79 matching lines @@
 
     DISALLOW_COPY_AND_ASSIGN(ConstantArraySlice);
   };
 
   const ConstantArraySlice* IndexToSlice(size_t index) const;
   ConstantArraySlice* OperandSizeToSlice(OperandSize operand_size) const;
 
   IdentityMap<index_t>* constants_map() { return &constants_map_; }
 
   Isolate* isolate_;
-  ConstantArraySlice* idx_slice_[2];
+  ConstantArraySlice* idx_slice_[3];
   IdentityMap<index_t> constants_map_;
 };
 
 }  // namespace interpreter
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_INTERPRETER_CONSTANT_ARRAY_BUILDER_H_