serve: make tests compatible with chg chg only supports 'hg serve' when the options to the serve command follow the 'hg serve'. For example, 'hg -R <repo> serve ..' is unsupported. This leads to issues with chg running for the following tests: - test-bundle2-exchange.t - test-clone-uncompressed.t - test-hgweb-csp.t - test-http-bad-server.t - test-http-bundle1.t - test-http-protocol.t - test-http.t There was an effort made earlier to fix this issue for chg and the tests were fixed to confirm to the compatible pattern. But the new tests did not take care of the same and hence, fail. Hopefully, there will be continuous build setup for chg after all tests are made compatible with chg so that we can avoid such issues. Test Plan: Ran the aforementioned tests with and without '--chg' option. Differential Revision: https://phab.mercurial-scm.org/D946