test: explicitly disable sparse-revlog in test-http-bad-server.t The `test-http-bad-server.t` test is very fragile with hard-coded number all around. Adding any new capability have massive consequences on it that are long and tiresome to handle. Since the test check more generic protocol level behavior, it does not need to follow all new capabilities. Disabling the capabilities is a much simpler way to avoid the issue. We make sure `sparse-revlog` will not impact this test once turned on by default. Differential Revision: https://phab.mercurial-scm.org/D5313