revset: fix commonancestor test so it demonstrates correct behavior The problem is that hg log -r 'head()' is every changeset in the repository, because in this test repository, every changeset has a different branch. The author probably assumed all commits were on the default branch, and that they were getting topological heads, 7 and 9. As a result, this test was showing that the common ancestors of 0:9 are 0+1+2+4, which is not correct (next commit will test this). Differential Revision: https://phab.mercurial-scm.org/D4736