bug#32088: Python >=3.5 test suite failures

[Karl Berry]

    instmany-python.sh from the somewhat arbitrary 2500 to 3200. Neverthlesss, 
    maybe a more elegant solution is possible.

Seems fine to me. Thanks for finding the workaround.

    2) The fix/patch of bug #38043 (Incorrect Python byte-compiling for
    Python 3 and PyPy3), which we also carry, interferes with
    t/py-compile-basedir.sh; the number of generated files (line 47
    there) is then (only for recent Python 3) 6, not 4.

People will surely be running make check on older machines.

Maybe the simplest way is just to accept either 4 or 6 in the stated
 test $(echo "$files" | wc -l) -eq 4
as long as those are the only results ... so far ...

Jim, wdyt? --thanks, karl.