[turbofan] Add a Simplified::CheckMaps instruction.

src/compiler/simplified-operator.cc

Index: src/compiler/simplified-operator.cc
diff --git a/src/compiler/simplified-operator.cc b/src/compiler/simplified-operator.cc
index 9b34668d5c4e43466364237260116646d75ef4ff..d9fd73eaec65affdfefd8330f480a9118330cdf5 100644
--- a/src/compiler/simplified-operator.cc
+++ b/src/compiler/simplified-operator.cc
@@ -234,6 +234,15 @@ PURE_OP_LIST(PURE)
 #undef PURE
 
 
+const Operator* SimplifiedOperatorBuilder::CheckMaps(int map_count) {
+  DCHECK_GE(map_count, 1);
+  // TODO(turbofan): cache CheckMaps operators
+  return new (zone()) Operator1<int32_t>(
+      IrOpcode::kCheckMaps, Operator::kNoWrite | Operator::kNoThrow,
+      "CheckMaps", 1 + map_count, 1, 1, 0, 0, 1, map_count);
+}
+
+
 const Operator* SimplifiedOperatorBuilder::ReferenceEqual(Type* type) {
   // TODO(titzer): What about the type parameter?
   return new (zone()) Operator(IrOpcode::kReferenceEqual,