tests: don't run couple of tests related to extensions loading with chg
The couple of files test extensions loading and debugging that. It sets
`devel.debug.extensions` to True to do that.
Either we have to restart chg if this config is set or just don't run these
tests on chg. I tried the first way by adding the config option to chgserver.py
list of config subsections but that does not seem to work.
To run the tests, do:
cd tests/
python run-tests.py
See https://mercurial-scm.org/wiki/WritingTests for
more information on writing tests.