[turbofan] Emit explicit checkpoint before operations.

src/compiler/effect-control-linearizer.cc

Index: src/compiler/effect-control-linearizer.cc
diff --git a/src/compiler/effect-control-linearizer.cc b/src/compiler/effect-control-linearizer.cc
index 2e597383ffc78f5adc3a5596a52630ca5b9f8156..8d967b111c382a65a8a7233222d7ecf5395430e8 100644
--- a/src/compiler/effect-control-linearizer.cc
+++ b/src/compiler/effect-control-linearizer.cc
@@ -298,7 +298,7 @@ void EffectControlLinearizer::ProcessNode(Node* node, Node** effect,
   if (node->opcode() == IrOpcode::kCheckpoint) {
     // Unlink the check point; effect uses will be updated to the incoming
     // effect that is passed.
-    node->Kill();
+    node->TrimInputCount(0);
     return;
   }