[turbofan] Build s/NULL/nullptr/g and CHECK(x != nullptr) to CHECK_NOT_NULL(x).

src/compiler/raw-machine-assembler.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/raw-machine-assembler.h"
 
 #include "src/code-factory.h"
 #include "src/compiler/node-properties.h"
 #include "src/compiler/pipeline.h"
 #include "src/compiler/scheduler.h"
@@ skipping 340 matching lines @@
 
 BasicBlock* RawMachineAssembler::CurrentBlock() {
   DCHECK(current_block_);
   return current_block_;
 }
 
 
 Node* RawMachineAssembler::AddNode(const Operator* op, int input_count,
                                    Node** inputs) {
   DCHECK_NOT_NULL(schedule_);
-  DCHECK(current_block_ != nullptr);
+  DCHECK_NOT_NULL(current_block_);
   Node* node = MakeNode(op, input_count, inputs);
   schedule()->AddNode(CurrentBlock(), node);
   return node;
 }
 
 
 Node* RawMachineAssembler::MakeNode(const Operator* op, int input_count,
                                     Node** inputs) {
   // The raw machine assembler nodes do not have effect and control inputs,
   // so we disable checking input counts here.
   return graph()->NewNodeUnchecked(op, input_count, inputs);
 }
 
 
 RawMachineLabel::RawMachineLabel()
-    : block_(NULL), used_(false), bound_(false) {}
+    : block_(nullptr), used_(false), bound_(false) {}
 
 
 RawMachineLabel::~RawMachineLabel() { DCHECK(bound_ || !used_); }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8