Revert of Remove register index/code indirection

test/unittests/compiler/instruction-sequence-unittest.h

 // Copyright 2014 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_UNITTESTS_COMPILER_INSTRUCTION_SEQUENCE_UNITTEST_H_
 #define V8_UNITTESTS_COMPILER_INSTRUCTION_SEQUENCE_UNITTEST_H_
 
 #include "src/compiler/instruction.h"
 #include "test/unittests/test-utils.h"
 #include "testing/gmock/include/gmock/gmock.h"
 
 namespace v8 {
 namespace internal {
 namespace compiler {
 
 class InstructionSequenceTest : public TestWithIsolateAndZone {
  public:
-  static const int kDefaultNRegs = 8;
+  static const int kDefaultNRegs = 4;
   static const int kNoValue = kMinInt;
 
   typedef RpoNumber Rpo;
 
   struct VReg {
     VReg() : value_(kNoValue) {}
     VReg(PhiInstruction* phi) : value_(phi->virtual_register()) {}  // NOLINT
     explicit VReg(int value) : value_(value) {}
     int value_;
   };
@@ skipping 206 matching lines @@
   LoopBlocks loop_blocks_;
   InstructionBlock* current_block_;
   bool block_returns_;
 };
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_UNITTESTS_COMPILER_INSTRUCTION_SEQUENCE_UNITTEST_H_