GH-94808: Test __build_class__ inside non-dict __builtins__ (GH-95932) (#96004)

(cherry picked from commit 3adb4d8)

Co-authored-by: Michael Droettboom <mdboom@gmail.com>

Co-authored-by: Michael Droettboom <mdboom@gmail.com>

Author: miss-islington

Lib/test/test_builtin.py

@@ -737,11 +737,6 @@ def test_exec_globals(self):
         self.assertRaises(TypeError,
                           exec, code, {'__builtins__': 123})
 
-        # no __build_class__ function
-        code = compile("class A: pass", "", "exec")
-        self.assertRaisesRegex(NameError, "__build_class__ not found",
-                               exec, code, {'__builtins__': {}})
-
         class frozendict_error(Exception):
             pass
 
@@ -758,6 +753,15 @@ def __setitem__(self, key, value):
         self.assertRaises(frozendict_error,
                           exec, code, {'__builtins__': frozen_builtins})
 
+        # no __build_class__ function
+        code = compile("class A: pass", "", "exec")
+        self.assertRaisesRegex(NameError, "__build_class__ not found",
+                               exec, code, {'__builtins__': {}})
+        # __build_class__ in a custom __builtins__
+        exec(code, {'__builtins__': frozen_builtins})
+        self.assertRaisesRegex(NameError, "__build_class__ not found",
+                               exec, code, {'__builtins__': frozendict()})
+
         # read-only globals
         namespace = frozendict({})
         code = compile("x=1", "test", "exec")