tests: update some clonebundles expectations to pass on both pure and non-pure
Specifically, zstd isn't available in --pure mode, and we need to glob
off the leading comma as well as the absent compression engine.
Differential Revision: https://phab.mercurial-scm.org/D859
To run the tests, do:
cd tests/
python run-tests.py
See https://mercurial-scm.org/wiki/WritingTests for
more information on writing tests.