Revert now useless fix

Author: marc-chevalier

Diff for: src/hotspot/share/opto/library_call.cpp

@@ -4312,12 +4312,7 @@ Node* LibraryCallKit::generate_array_guard_common(Node* kls, RegionNode* region,
   if (obj != nullptr && is_array_ctrl != nullptr && is_array_ctrl != top()) {
     // Keep track of the fact that 'obj' is an array to prevent
     // array specific accesses from floating above the guard.
-    Node* cast = _gvn.transform(new CastPPNode(is_array_ctrl, *obj, TypeAryPtr::BOTTOM));
-    // Check for top because in rare cases, the type system can determine that
-    // the object can't be an array but the layout helper check is not folded.
-    if (!cast->is_top()) {
-      *obj = cast;
-    }
+    *obj = _gvn.transform(new CastPPNode(is_array_ctrl, *obj, TypeAryPtr::BOTTOM));
   }
   return ctrl;
 }