[turbofan] Turn common Guard operator into simplified TypeGuard.

src/compiler/common-operator-reducer.cc

Index: src/compiler/common-operator-reducer.cc
diff --git a/src/compiler/common-operator-reducer.cc b/src/compiler/common-operator-reducer.cc
index 22e16a27f266e2e4c8f363c8d9943de2f4077718..fad9b99aaa5fdfb0bee0886a7dfae197790eb6ce 100644
--- a/src/compiler/common-operator-reducer.cc
+++ b/src/compiler/common-operator-reducer.cc
@@ -70,8 +70,6 @@ Reduction CommonOperatorReducer::Reduce(Node* node) {
       return ReduceReturn(node);
     case IrOpcode::kSelect:
       return ReduceSelect(node);
-    case IrOpcode::kGuard:
-      return ReduceGuard(node);
     default:
       break;
   }
@@ -396,16 +394,6 @@ Reduction CommonOperatorReducer::ReduceSelect(Node* node) {
 }
 
 
-Reduction CommonOperatorReducer::ReduceGuard(Node* node) {
-  DCHECK_EQ(IrOpcode::kGuard, node->opcode());
-  Node* const input = NodeProperties::GetValueInput(node, 0);
-  Type* const input_type = NodeProperties::GetTypeOrAny(input);
-  Type* const guard_type = OpParameter<Type*>(node);
-  if (input_type->Is(guard_type)) return Replace(input);
-  return NoChange();
-}
-
-
 Reduction CommonOperatorReducer::Change(Node* node, Operator const* op,
                                         Node* a) {
   node->ReplaceInput(0, a);