[turbofan] Implicitly emit eager checkpoint at graph building.

src/full-codegen/full-codegen.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/full-codegen/full-codegen.h"
 
 #include "src/ast/ast-numbering.h"
 #include "src/ast/ast.h"
 #include "src/ast/prettyprinter.h"
 #include "src/ast/scopeinfo.h"
@@ skipping 873 matching lines @@
     VisitStatements(stmt->statements());
     __ bind(nested_block.break_label());
   }
 }
 
 
 void FullCodeGenerator::VisitDoExpression(DoExpression* expr) {
   Comment cmnt(masm_, "[ Do Expression");
   SetExpressionPosition(expr);
   VisitBlock(expr->block());
-  EmitVariableLoad(expr->result());
+  VisitInDuplicateContext(expr->result());
 }
 
 
 void FullCodeGenerator::VisitExpressionStatement(ExpressionStatement* stmt) {
   Comment cmnt(masm_, "[ ExpressionStatement");
   SetStatementPosition(stmt);
   VisitForEffect(stmt->expression());
 }
 
 
@@ skipping 1081 matching lines @@
   return var->scope()->is_nonlinear() ||
          var->initializer_position() >= proxy->position();
 }
 
 
 #undef __
 
 
 }  // namespace internal
 }  // namespace v8