Harmonize the bottom of the outer loop with its entry point
giving a small simplification.  Timings show that hash
pre-check seems only benefit the inner-loop (the linear probes).
diff --git a/Objects/setobject.c b/Objects/setobject.c
index d621647..70ec644 100644
--- a/Objects/setobject.c
+++ b/Objects/setobject.c
@@ -118,7 +118,7 @@
         i = (i * 5 + 1 + perturb) & mask;
 
         entry = &table[i];
-        if (entry->hash == 0 && entry->key == NULL)
+        if (entry->key == NULL)
             return entry;
     }
 }
@@ -206,7 +206,7 @@
         i = (i * 5 + 1 + perturb) & mask;
 
         entry = &table[i];
-        if (entry->hash == 0 && entry->key == NULL)
+        if (entry->key == NULL)
             goto found_null;
     }