HPCC-11325 Include argparse.py in regression suite

Add argparse.py to regress/hpcc/util directory

Modify ecl-test to use argparse from util directory

Signed-off-by: Attila Vamos <attila.vamos@gmail.com>
Merge pull request #5891 from AttilaVamos/HPCC-11325-fix2

HPCC-11325 Include argparse.py in regression suite

Reviewed-By: Richard Chapman <rchapman@hpccsystems.com>