Don't use the keyed slow stub for named handlers.

src/ic/ic.cc

Index: src/ic/ic.cc
diff --git a/src/ic/ic.cc b/src/ic/ic.cc
index d6c93bfe9ac1c0be9039c5df1b517145a831ce58..bc667619904ec8726333e28f71883d47d76c6048 100644
--- a/src/ic/ic.cc
+++ b/src/ic/ic.cc
@@ -1436,12 +1436,7 @@ Handle<Code> StoreIC::initialize_stub_in_optimized_code(
 }
 
 Handle<Code> StoreIC::slow_stub() const {
-  if (kind() == Code::STORE_IC) {
-    return isolate()->builtins()->StoreIC_Slow();
-  } else {
-    DCHECK(kind() == Code::KEYED_STORE_IC);
-    return isolate()->builtins()->KeyedStoreIC_Slow();
-  }
+  return isolate()->builtins()->StoreIC_Slow();
 }