[turbofan] Rename {CheckPoint} to {Checkpoint} everywhere.

test/unittests/compiler/checkpoint-elimination-unittest.cc

 // Copyright 2016 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/checkpoint-elimination.h"
 #include "src/compiler/common-operator.h"
 #include "src/compiler/operator.h"
 #include "test/unittests/compiler/graph-reducer-unittest.h"
 #include "test/unittests/compiler/graph-unittest.h"
 #include "test/unittests/compiler/node-test-utils.h"
@@ skipping 21 matching lines @@
   }
 };
 
 namespace {
 
 const Operator kOpNoWrite(0, Operator::kNoWrite, "OpNoWrite", 0, 1, 0, 0, 1, 0);
 
 }  // namespace
 
 // -----------------------------------------------------------------------------
-// CheckPoint
+// Checkpoint
 
-TEST_F(CheckpointEliminationTest, CheckPointChain) {
+TEST_F(CheckpointEliminationTest, CheckpointChain) {
   Node* const control = graph()->start();
   Node* frame_state = EmptyFrameState();
-  Node* checkpoint1 = graph()->NewNode(common()->CheckPoint(), frame_state,
+  Node* checkpoint1 = graph()->NewNode(common()->Checkpoint(), frame_state,
                                        graph()->start(), control);
   Node* effect_link = graph()->NewNode(&kOpNoWrite, checkpoint1);
-  Node* checkpoint2 = graph()->NewNode(common()->CheckPoint(), frame_state,
+  Node* checkpoint2 = graph()->NewNode(common()->Checkpoint(), frame_state,
                                        effect_link, control);
   Reduction r = Reduce(checkpoint2);
   ASSERT_TRUE(r.Changed());
   EXPECT_EQ(effect_link, r.replacement());
 }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8