Fix redundant return for python 2.7

[wangym5106]

For example:

def test():
    c = 1

Decompiled result:

# uncompyle6 version 3.9.3.dev0
# Python bytecode version base 2.7 (62211)
# Decompiled from: Python 3.8.10 (tags/v3.8.10:3d8993a, May  3 2021, 11:48:03) [MSC v.1928 64 bit (AMD64)]
# Embedded file name: /cwd/test.py
# Compiled at: 2025-11-21 19:12:13
def test():
    c = 1
    return


return

# okay decompiling .\test.pyc

This issue is caused by 4ac5564, will produce redundant return for every function in python 2.7.
This PR will fix it.