scripts: Replaced __builtins__ with builtins

Apparently __builtins__ is a CPython implementation detail, and behaves
differently when executed vs imported???

import builtins is the correct way to go about this.

scripts/perfbd.py

@@ -829,7 +829,8 @@ def table(Result, results, diff_results=None, *,
         depth=1,
         hot=None,
         **_):
-    all_, all = all, __builtins__.all
+    import builtins
+    all_, all = all, builtins.all
 
     if by is None:
         by = Result._by