[turbofan] Add a Simplified::CheckMaps instruction.

src/compiler/simplified-lowering.h

Index: src/compiler/simplified-lowering.h
diff --git a/src/compiler/simplified-lowering.h b/src/compiler/simplified-lowering.h
index 124090efb5d0b6c8d022c25e3db5f67cbf7b639f..26e43d84a54d09817f28cd73b990fdd5ada2200c 100644
--- a/src/compiler/simplified-lowering.h
+++ b/src/compiler/simplified-lowering.h
@@ -42,6 +42,7 @@ class SimplifiedLowering final {
   void DoStringEqual(Node* node);
   void DoStringLessThan(Node* node);
   void DoStringLessThanOrEqual(Node* node);
+  void DoCheckMaps(Node* node);
 
  private:
   JSGraph* const jsgraph_;
@@ -56,6 +57,7 @@ class SimplifiedLowering final {
 
   Node* SmiTag(Node* node);
   Node* IsTagged(Node* node);
+  Node* IsSmi(Node* node);
   Node* Untag(Node* node);
   Node* OffsetMinusTagConstant(int32_t offset);
   Node* ComputeIndex(const ElementAccess& access, Node* const key);
@@ -65,6 +67,8 @@ class SimplifiedLowering final {
   Node* Uint32Div(Node* const node);
   Node* Uint32Mod(Node* const node);
 
+  void AddDeoptimize(Node* frame_state_before, Node* effect, Node* control);
+
   friend class RepresentationSelector;
 
   Zone* zone() { return jsgraph_->zone(); }