[interpreter] Drop overprotective --harmony-instanceof check.

src/interpreter/bytecode-array-builder.cc

 // 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.
 
 #include "src/interpreter/bytecode-array-builder.h"
 #include "src/compiler.h"
 
 namespace v8 {
 namespace internal {
 namespace interpreter {
@@ skipping 1415 matching lines @@
       return Bytecode::kTestEqualStrict;
     case Token::Value::LT:
       return Bytecode::kTestLessThan;
     case Token::Value::GT:
       return Bytecode::kTestGreaterThan;
     case Token::Value::LTE:
       return Bytecode::kTestLessThanOrEqual;
     case Token::Value::GTE:
       return Bytecode::kTestGreaterThanOrEqual;
     case Token::Value::INSTANCEOF:
-      DCHECK(!FLAG_harmony_instanceof);
       return Bytecode::kTestInstanceOf;
     case Token::Value::IN:
       return Bytecode::kTestIn;
     default:
       UNREACHABLE();
       return static_cast<Bytecode>(-1);
   }
 }
 
 
@@ skipping 193 matching lines @@
 }
 
 // static
 bool BytecodeArrayBuilder::FitsInReg16OperandUntranslated(Register value) {
   return value.is_short_operand();
 }
 
 }  // namespace interpreter
 }  // namespace internal
 }  // namespace v8