[stubs] Port LoadScriptContextFieldStub and StoreScriptContextFieldStub to TurboFan.

src/crankshaft/hydrogen.cc

 // Copyright 2013 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/hydrogen.h"
 
 #include <memory>
 #include <sstream>
 
 #include "src/allocation-site-scopes.h"
@@ skipping 3384 matching lines @@
 HInstruction* HGraphBuilder::BuildGetNativeContext(HValue* closure) {
   // Get the global object, then the native context
   HInstruction* context = Add<HLoadNamedField>(
       closure, nullptr, HObjectAccess::ForFunctionContextPointer());
   return Add<HLoadNamedField>(
       context, nullptr,
       HObjectAccess::ForContextSlot(Context::NATIVE_CONTEXT_INDEX));
 }
 
 
-HInstruction* HGraphBuilder::BuildGetScriptContext(int context_index) {
-  HValue* native_context = BuildGetNativeContext();
-  HValue* script_context_table = Add<HLoadNamedField>(
-      native_context, nullptr,
-      HObjectAccess::ForContextSlot(Context::SCRIPT_CONTEXT_TABLE_INDEX));
-  return Add<HLoadNamedField>(script_context_table, nullptr,
-                              HObjectAccess::ForScriptContext(context_index));
-}
-
-
 HValue* HGraphBuilder::BuildGetParentContext(HValue* depth, int depth_value) {
   HValue* script_context = context();
   if (depth != NULL) {
     HValue* zero = graph()->GetConstant0();
 
     Push(script_context);
     Push(depth);
 
     LoopBuilder loop(this);
     loop.BeginBody(2);  // Drop script_context and depth from last environment
@@ skipping 9970 matching lines @@
     isolate()->GetHTracer()->TraceHydrogen(name(), graph_);
   }
 
 #ifdef DEBUG
   graph_->Verify(false);  // No full verify.
 #endif
 }
 
 }  // namespace internal
 }  // namespace v8