[devctl] Optimize cleanup_sys_modules a bit
by moving out of a loop a costly computation that is constant.
This at least benefits the `i18ncube` command.
Related to #15789486.
@echo off
rem = """-*-Python-*- script
rem -------------------- DOS section --------------------
rem You could set PYTHONPATH or TK environment variables here
python -x "%~f0" %*
goto exit
"""
# -------------------- Python section --------------------
import sys
from os.path import join, dirname, normpath
sys.path.insert(0, normpath(join(dirname(__file__), '..', '..')))
from cubicweb.cwctl import run
run(sys.argv[1:])
DosExitLabel = """
:exit
rem """