[turbofan] Introduce CheckPoint common operator.

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 dabf52dce4d88cf3eaba9867e753634d3fdda6c3..f093d405ab15d164c0eeedd62c9a3229468ca7e7 100644
--- a/src/compiler/effect-control-linearizer.cc
+++ b/src/compiler/effect-control-linearizer.cc
@@ -293,6 +293,15 @@ void EffectControlLinearizer::ProcessNode(Node* node, Node** effect,
     return RemoveRegionNode(node);
   }
 
+  // Special treatment for CheckPoint nodes.
+  // TODO(epertoso): Pickup the current frame state.
+  if (node->opcode() == IrOpcode::kCheckPoint) {
+    // Unlink the check point; effect uses will be updated to the incoming
+    // effect that is passed.
+    node->Kill();
+    return;
+  }
+
   if (node->opcode() == IrOpcode::kIfSuccess) {
     // We always schedule IfSuccess with its call, so skip it here.
     DCHECK_EQ(IrOpcode::kCall, node->InputAt(0)->opcode());