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

src/compiler/node.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/compiler/node.h"
 
 namespace v8 {
 namespace internal {
 namespace compiler {
 
@@ skipping 42 matching lines @@
                 Node* const* inputs, bool has_extensible_inputs) {
   Node** input_ptr;
   Use* use_ptr;
   Node* node;
   bool is_inline;
 
 #if DEBUG
   // Verify that none of the inputs are {nullptr}.
   for (int i = 0; i < input_count; i++) {
     if (inputs[i] == nullptr) {
-      V8_Fatal(__FILE__, __LINE__, "Node::New() Error: #%d:%s[%d] is NULL",
-            static_cast<int>(id), op->mnemonic(), i);
+      V8_Fatal(__FILE__, __LINE__, "Node::New() Error: #%d:%s[%d] is nullptr",
+               static_cast<int>(id), op->mnemonic(), i);
     }
   }
 #endif
 
   if (input_count > kMaxInlineCapacity) {
     // Allocate out-of-line inputs.
     int capacity =
         has_extensible_inputs ? input_count + kMaxInlineCapacity : input_count;
     OutOfLineInputs* outline = OutOfLineInputs::New(zone, capacity);
 
@@ skipping 337 matching lines @@
   ++(*this);
   return result;
 }
 
 
 bool Node::Uses::empty() const { return begin() == end(); }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8