[turbofan] Introduce CheckIf simplified operator.

src/compiler/js-call-reducer.h

Index: src/compiler/js-call-reducer.h
diff --git a/src/compiler/js-call-reducer.h b/src/compiler/js-call-reducer.h
index 9ffae152ac08b76b168c0303c55327896110fda4..8d9700a0720d6368315cc6a93edead1734040afd 100644
--- a/src/compiler/js-call-reducer.h
+++ b/src/compiler/js-call-reducer.h
@@ -16,7 +16,7 @@ namespace compiler {
 class CommonOperatorBuilder;
 class JSGraph;
 class JSOperatorBuilder;
-
+class SimplifiedOperatorBuilder;
 
 // Performs strength reduction on {JSCallConstruct} and {JSCallFunction} nodes,
 // which might allow inlining or other optimizations to be performed afterwards.
@@ -52,6 +52,7 @@ class JSCallReducer final : public Reducer {
   MaybeHandle<Context> native_context() const { return native_context_; }
   CommonOperatorBuilder* common() const;
   JSOperatorBuilder* javascript() const;
+  SimplifiedOperatorBuilder* simplified() const;
 
   JSGraph* const jsgraph_;
   Flags const flags_;