tests: don't drop global hgrc Various tests are failing when the simple store extension is loaded because the test overrides HGRCPATH and preempts loading of extensions that were injected via --extra-config-opt. In most cases, it is acceptable to always load the global HGRCPATH. So this commit changes a couple of tests so the global HGRCPATH is still pulled in. Differential Revision: https://phab.mercurial-scm.org/D3098