tests: update py3 test since json fields are now sorted
The fields have been sorted since 814151cd8c4a (logcmdutil: rewrite
jsonchangeset printer to be backed by jsonformatter, 2018-04-13), and
the test case has thus been failing since that commit.
Differential Revision: https://phab.mercurial-scm.org/D3570
To run the tests, do:
cd tests/
python run-tests.py
See https://mercurial-scm.org/wiki/WritingTests for
more information on writing tests.