"pickle1" and "pickle4" unit tests fail with Python 3.11

[sunyab]

Both "pickle1" and "pickle4" fail when boost::python is built against Python 3.11 or later. I've pasted in the test output below.

I believe these failures are due to the addition of object.__getstate__ documented in this section: https://docs.python.org/3/whatsnew/3.11.html#other-language-changes

====== BEGIN OUTPUT ======
running...
**********************************************************************
File "/root/boost_1_86_0/libs/python/test/pickle1.py", line 12, in __main__
Failed example:
    pickle1_ext.world('Hello').__reduce__()
Expected:
    (<class 'pickle1_ext.world'>, ('Hello',))
Got:
    (<class 'pickle1_ext.world'>, ('Hello',), None)
**********************************************************************
1 items had failures:
   1 of  13 in __main__
***Test Failed*** 1 failures.

EXIT STATUS: 1
====== END OUTPUT ======

====== BEGIN OUTPUT ======
running...
**********************************************************************
File "/root/boost_1_86_0/libs/python/test/pickle4.py", line 15, in __main__
Failed example:
    pickle4_ext.world('Hello').__reduce__()
Expected:
    (<class 'pickle4_ext.world'>, ('Hello',))
Got:
    (<class 'pickle4_ext.world'>, ('Hello',), None)
**********************************************************************
1 items had failures:
   1 of  13 in __main__
***Test Failed*** 1 failures.

EXIT STATUS: 1
====== END OUTPUT ======

This was originally reported here: PixarAnimationStudios/OpenUSD#3384