All tests in bin/tests/system/statschannel/tests-json.py require json-c
support to be enabled in BIND 9 at build-time. Instead of applying the
same pytest.mark.skipif() decorator to every test in that file, set the
'pytestmark' global accordingly in order to immediately skip all tests
in tests-json.py if json-c support is not compiled in.
Remove all occurrences of the @pytest.mark.json decorator (and all
associated code) from the "statschannel" system test as the json module
is a part of the Python standard library since Python 2.6 (so checking
whether it is available is redundant) and checking for json-c support in
the tested BIND 9 build is already handled by setting the 'pytestmark'
global accordingly.
Also remove a related excerpt from bin/tests/system/rpzextra/conftest.py
as it is a copy-paste artifact that serves no purpose in the "rpzextra"
system test.
(cherry picked from commit 0a76f186a5)
3680763577