test-glog.t: use printrevset extension to trace rewritten revsets Using "hg log -G --print-revset" prints the revset generated by graphlog and exits. This helps debugging and writing shorter tests. It has been suggested to handle these tests with doctests. I think the extension approach is better because: - It tests the actual parameter set passed to graphlog.revset(), not what we expect it to be. 'branch' and 'only-branch' are currently distinct options but nothing prevents fancyopts to grow a notion of option aliasing one day, where both options would be merged before reaching the command. - It can be used as debug output interleaved with real log calls. v2: - Use a test extension instead of a global deprecated new option