Revert of [turbofan] Introduce LoadFunctionPrototype simplified operator.

src/compiler/simplified-operator.h

Index: src/compiler/simplified-operator.h
diff --git a/src/compiler/simplified-operator.h b/src/compiler/simplified-operator.h
index c21b97dc31597ffbb289e28e32f2a7007f24f320..833a0554f588b11dc3af3f85c16223fa61c32d1e 100644
--- a/src/compiler/simplified-operator.h
+++ b/src/compiler/simplified-operator.h
@@ -390,9 +390,6 @@
   // store-typed-element buffer, [base + external + index], value
   const Operator* StoreTypedElement(ExternalArrayType const&);
 
-  // load-function-prototype function
-  const Operator* LoadFunctionPrototype();
-
  private:
   Zone* zone() const { return zone_; }