[Interpreter] Add support for calling runtime functions which return a pair.

src/interpreter/bytecode-array-iterator.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-iterator.h"
 
 #include "src/objects-inl.h"
 
 namespace v8 {
 namespace internal {
@@ skipping 70 matching lines @@
          operand_type == OperandType::kIdx16);
   uint32_t operand = GetRawOperand(operand_index, operand_type);
   return static_cast<int>(operand);
 }
 
 
 Register BytecodeArrayIterator::GetRegisterOperand(int operand_index) const {
   OperandType operand_type =
       Bytecodes::GetOperandType(current_bytecode(), operand_index);
   DCHECK(operand_type == OperandType::kReg8 ||
+         operand_type == OperandType::kRegPair8 ||
          operand_type == OperandType::kMaybeReg8 ||
          operand_type == OperandType::kReg16);
   uint32_t operand = GetRawOperand(operand_index, operand_type);
   return Register::FromOperand(operand);
 }
 
 
 Handle<Object> BytecodeArrayIterator::GetConstantForIndexOperand(
     int operand_index) const {
   Handle<FixedArray> constants = handle(bytecode_array()->constant_pool());
@@ skipping 12 matching lines @@
     return current_offset() + smi->value();
   } else {
     UNREACHABLE();
     return kMinInt;
   }
 }
 
 }  // namespace interpreter
 }  // namespace internal
 }  // namespace v8