testing/tests/package/test_python: add TestPython3

Add Python3 version of TestPython2 to make sure both versions of
Python get unit-tested.

Modify the code of libc_time_test() to support that change (convert
the code to use Python3-style "print").

Signed-off-by: Andrey Smirnov <andrew.smirnov@gmail.com>
[Thomas: update .gitlab-ci.yml.]
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
2 files changed