tests: test using both versions of SSH protocol Now that the version 2 of the SSH protocol is usable in core, we can start actively testing it more widely outside of low-level protocol tests. We add #testcases variants to a handful of tests so we exercise both version 1 and version 2 of the SSH protocol when testing. This will allow us to more easily find regressions and variances as protocol 2 is developed. It will also make it easier to continue testing with protocol version 1 once version 2 is enabled by default. There are a handful of tests using ssh:// that should also gain test variances. One - test-push-race.t - already has a #testcases. This would require combinatorial cases. I didn't want to go down that rabbit hole, so that test is unchanged. Thinking aloud, there is probably an opportunity to automatically run tests with multiple server/protocol implementations. Ideally any test that performed server interaction would run with all supported server implementations and protocols so we could find variances between servers and protocols. But this has been a long-standing issue with our test harness. I don't think it is an easily solved problem. But it would be nice... Differential Revision: https://phab.mercurial-scm.org/D2206

% lazy ancestor set for [], stoprev = 0, inclusive = False
membership: []
iteration:  []
% lazy ancestor set for [11, 13], stoprev = 0, inclusive = False
membership: [7, 8, 3, 4, 1, 0]
iteration:  [3, 7, 8, 1, 4, 0, 2]
% lazy ancestor set for [1, 3], stoprev = 0, inclusive = False
membership: [1, 0]
iteration:  [0, 1]
% lazy ancestor set for [11, 13], stoprev = 0, inclusive = True
membership: [11, 13, 7, 8, 3, 4, 1, 0]
iteration:  [11, 13, 3, 7, 8, 1, 4, 0, 2]
% lazy ancestor set for [11, 13], stoprev = 6, inclusive = False
membership: [7, 8]
iteration:  [7, 8]
% lazy ancestor set for [11, 13], stoprev = 6, inclusive = True
membership: [11, 13, 7, 8]
iteration:  [11, 13, 7, 8]