Creating the parsetab.py cache file in a system wide fixed location
(e.g. /tmp/parsetab.py) creates problems when a computer is used by
different users. Also the file is never removed, which is not very nice.
Caching provides hardly any benefit here, as it only takes milliseconds,
and may even be negated by the additional required filesystem operations.
Fixes (part of) #6315.
7cac8787a4