Fix format for the __sizeof__ test.

Author: serhiy-storchaka

Lib/test/test_struct.py

@@ -594,7 +594,7 @@ def test_Struct_reinitialization(self):
 
     def check_sizeof(self, format_str, number_of_codes):
         # The size of 'PyStructObject'
-        totalsize = support.calcobjsize('2n3P1?')
+        totalsize = support.calcobjsize('2n3P?0P')
         # The size taken up by the 'formatcode' dynamic array
         totalsize += struct.calcsize('P3n0P') * (number_of_codes + 1)
         support.check_sizeof(self, struct.Struct(format_str), totalsize)