selftest/flapping.d: Add python2 versions for flapping tests

selftest/flapping.d: Add python2 versions for flapping tests

Post build & test running under python3 we now run with
'--extra-python=/usr/bin/python2',  these tests will get
python2 appended to the test name so we need also to create
new flapping*/* entries for these. We will keep the python3
versions in case we create some CI job(s)
with
    PYTHON=python configure.developer --extra-python=/usr/bin/python3

Signed-off-by: Noel Power <noel.power@suse.com>
Reviewed-by: Andrew Bartlett <abartlet@samba.org>