bpo-34373: fix test_mktime and test_pthread_getcpuclickid tests on AIX

[aixtools]

fix test_mktime and test_pthread_getcpuclickid tests
add range checking for _PyTime_localtime (for AIX)

https://bugs.python.org/issue34373

[pablogsal]

Please, use braces here according to PEP 7.

[pablogsal]

Please, put the braces in the same line as the "if" (https://www.python.org/dev/peps/pep-0007/#id5)

[aixtools]

Actually, I was wondering if this might be useful for other platforms as well (that cannot handle negative times) - so I put it in additional brackets. I'll use your recommendation and make it "AIX only".

[pablogsal]

@aixtools Mi comment only refers to a style issue (the braces should open on the same line and not in a new line:

if (year < 70) do {
...
}

as opposed to

if (year < 70) do 
{
...
}

[ncoghlan]

This mostly looks good to me, just one question regarding whether or not the ctypes dependency in the test case can be avoided (hence the approving review, rather than an immediate merge).

[vstinner]

tt is now modified before it is checked if it's equal to (time_t)-1. It looks like a regression to me: I wrote PR #12726 to propose a fix.