_memoize_make_cache_key make different cache keys with int and long type integer

[lishubing]

_memoize_make_cache_key generate cache key simply using the arguments tuple, but in Python2, int and long type of arguments tuple will be turn different strings:

>>> [int(1)]
[1]
>>> [long(1)]
[1L]

so delete_memoized(func, 1) won't clear the cache result of func(1L).