Revert of [turbofan] Implicitly emit eager checkpoint at graph building.

src/compiler/checkpoint-elimination.cc

Index: src/compiler/checkpoint-elimination.cc
diff --git a/src/compiler/checkpoint-elimination.cc b/src/compiler/checkpoint-elimination.cc
index ce1a86105671088a2e0e9ec82dcad6a3573ca2a5..d81e1096820fbfba966ba1b34f6ee12bd8cac358 100644
--- a/src/compiler/checkpoint-elimination.cc
+++ b/src/compiler/checkpoint-elimination.cc
@@ -30,35 +30,10 @@
 
 }  // namespace
 
-Reduction CheckpointElimination::ReduceCheckpoint(Node* node) {
-  DCHECK_EQ(IrOpcode::kCheckpoint, node->opcode());
+Reduction CheckpointElimination::Reduce(Node* node) {
+  if (node->opcode() != IrOpcode::kCheckpoint) return NoChange();
   if (IsRedundantCheckpoint(node)) {
     return Replace(NodeProperties::GetEffectInput(node));
-  }
-  return NoChange();
-}
-
-Reduction CheckpointElimination::ReduceReturn(Node* node) {
-  DCHECK_EQ(IrOpcode::kReturn, node->opcode());
-  Node* effect = NodeProperties::GetEffectInput(node);
-  if (effect->opcode() == IrOpcode::kCheckpoint && effect->OwnedBy(node)) {
-    // Any checkpoint that is wholly owned by a {Return} node can never be used
-    // for an actual bailout and can hence be cut out of the effect chain.
-    Node* replacement = NodeProperties::GetEffectInput(effect);
-    NodeProperties::ReplaceEffectInput(node, replacement);
-    return Changed(node);
-  }
-  return NoChange();
-}
-
-Reduction CheckpointElimination::Reduce(Node* node) {
-  switch (node->opcode()) {
-    case IrOpcode::kCheckpoint:
-      return ReduceCheckpoint(node);
-    case IrOpcode::kReturn:
-      return ReduceReturn(node);
-    default:
-      break;
   }
   return NoChange();
 }