[turbofan] Remove the JSContextRelaxation reducer.

src/compiler/ast-graph-builder.cc

 // 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.
 
 #include "src/compiler/ast-graph-builder.h"
 
 #include "src/ast/scopes.h"
 #include "src/compiler.h"
 #include "src/compiler/ast-loop-assignment-analyzer.h"
 #include "src/compiler/control-builders.h"
@@ skipping 462 matching lines @@
       input_buffer_size_(0),
       input_buffer_(nullptr),
       exit_controls_(local_zone),
       loop_assignment_analysis_(loop),
       type_hint_analysis_(type_hint_analysis),
       state_values_cache_(jsgraph),
       liveness_analyzer_(static_cast<size_t>(info->scope()->num_stack_slots()),
                          local_zone),
       frame_state_function_info_(common()->CreateFrameStateFunctionInfo(
           FrameStateType::kJavaScriptFunction, info->num_parameters() + 1,
-          info->scope()->num_stack_slots(), info->shared_info(),
-          CALL_MAINTAINS_NATIVE_CONTEXT)) {
+          info->scope()->num_stack_slots(), info->shared_info())) {
   InitializeAstVisitor(info->isolate());
 }
 
 
 Node* AstGraphBuilder::GetFunctionClosureForContext() {
   Scope* closure_scope = current_scope()->ClosureScope();
   if (closure_scope->is_script_scope() ||
       closure_scope->is_module_scope()) {
     // Contexts nested in the native context have a canonical empty function as
     // their closure, not the anonymous closure containing the global code.
@@ skipping 3850 matching lines @@
     // Phi does not exist yet, introduce one.
     value = NewPhi(inputs, value, control);
     value->ReplaceInput(inputs - 1, other);
   }
   return value;
 }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8