tests: conditionalize test-phases.t output for chg IIUC chg loads the ProgrammingError class which leads to it directly referencing it in error output. This makes the test pass on chg.

chg: be stricter about checking invocation of `serve` command Few tests run serve command in form of `hg -R <repo> serve` which leads to chg thinking that it's not a serve command and failing tests. We become more stricter in checking for the serve command. This fixes test-server-view.t, test-remote-hidden.t, test-remotefilelog-http.t, test-phases-exchange.t, test-wireproto-content-redirects.t with chg.

chgserver: add merge-tools to sensitive config items Because this can change whether the ui is gui or not. This fixes test-extdiff.t with chg.

run-tests: add --chg-debug flag to show chg debug output This has helped me a lot in debugging chg failures in tests.

tests: update test-ssh.t output with --chg The output change was caused by d7304434390f5efca405744fa12a6585edae3d83.

tests: update test-devel-warnings.t output with chg The output change was caused by dc9901558e3c6a78bad3f6594b3888f95104c443.

chgserver: add fastannotate config section to sensitive list Depending on the config value of `fastannotate.modes`, the fastannotate extension can do different things in uisetup. Depending on value of `fastannotate.server`, it can register new wireprotocol capabilities. This fixes test-fastannotate-hg.t, test-fastannotate-protocol.t and test-fastannotate.t with chg.