[Interpreter] Fix a register allocation bug and add a DCHECK.

src/interpreter/bytecode-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_BYTECODE_ARRAY_BUILDER_H_
 #define V8_INTERPRETER_BYTECODE_ARRAY_BUILDER_H_
 
 #include <vector>
 
 #include "src/ast.h"
@@ skipping 298 matching lines @@
 // using result scopes as far as possible.
 class TemporaryRegisterScope {
  public:
   explicit TemporaryRegisterScope(BytecodeArrayBuilder* builder);
   ~TemporaryRegisterScope();
   Register NewRegister();
 
   void PrepareForConsecutiveAllocations(size_t count);
   Register NextConsecutiveRegister();
 
+  bool RegisterIsAllocatedInThisScope(Register reg) const;
+
  private:
   void* operator new(size_t size);
   void operator delete(void* p);
 
   BytecodeArrayBuilder* builder_;
   const TemporaryRegisterScope* outer_;
   ZoneVector<int> allocated_;
   int next_consecutive_register_;
   int next_consecutive_count_;
 
   DISALLOW_COPY_AND_ASSIGN(TemporaryRegisterScope);
 };
 
 
 }  // namespace interpreter
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_INTERPRETER_BYTECODE_ARRAY_BUILDER_H_