test-extension: make the test compatible with chg
This test fails when run with chg. This commit just makes the test chg
aware by fixing the output of some of the tests.
Test Plan:
Ran the test 'test-extension.t' with and without '--chg' option.
Differential Revision: https://phab.mercurial-scm.org/D1160
{
"conduit_uri": "https://phab.mercurial-scm.org/api",
"repository.callsign": "HG",
"arc.land.onto.default": "@",
"base": "hg:.^"
}