tests: make hg frame optional When `hg` is a Rust binary, the `hg` frame doesn't exist because an `hg` Python script doesn't exist. This commit updates expected test output to make the `hg` frame optional. There /might/ be a way to do this more accurately with the "(feature !)" syntax in .t files. However, I poked at it for a few minutes and couldn't get it to work. Worst case with using (?) is we drop the frame from output for Python `hg`. The `hg` frame isn't terribly important. So the worst case doesn't feel that bad. If someone wants to enlighten me on how to use "(feature !)" for optional output based on hghave features, I'd be more than willing to update this. Differential Revision: https://phab.mercurial-scm.org/D1858