[crankshaft] Remove the useless HAllocateBlockContext instruction.

src/crankshaft/x64/lithium-x64.cc

 // Copyright 2012 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/crankshaft/x64/lithium-x64.h"
 
 #include <sstream>
 
 #if V8_TARGET_ARCH_X64
 
@@ skipping 2638 matching lines @@
   return AssignPointerMap(result);
 }
 
 
 LInstruction* LChunkBuilder::DoStoreFrameContext(HStoreFrameContext* instr) {
   LOperand* context = UseRegisterAtStart(instr->context());
   return new(zone()) LStoreFrameContext(context);
 }
 
 
-LInstruction* LChunkBuilder::DoAllocateBlockContext(
-    HAllocateBlockContext* instr) {
-  LOperand* context = UseFixed(instr->context(), rsi);
-  LOperand* function = UseRegisterAtStart(instr->function());
-  LAllocateBlockContext* result =
-      new(zone()) LAllocateBlockContext(context, function);
-  return MarkAsCall(DefineFixed(result, rsi), instr);
-}
-
-
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_TARGET_ARCH_X64