python: Avoid exceeding command-line length limit
With Python implementations following PEP-3174, a large number of files
are installed in the ‘__pycache__’ directory. As a consequence
“t/instmany-python.sh” test was failing due to the
‘uninstall-pythonPYTHON’ target deleting installed files in a single
‘rm’ command. Doing that in multiple steps avoids exceeding the
command-line length limit. This fixes bug#30335.
* lib/am/python.am (uninstall-%DIR%PYTHON): For byte-compiled files
installed in '__pycache__' directory, uninstall them by batch of 40.
[?FIRST?] (am__pep3147_tweak): Adapt.