Merge branch 'ps/connectivity-optim'

The revision traversal API has been optimized by taking advantage of the commit-graph, when available, to determine if a commit is reachable from any of the existing refs. * ps/connectivity-optim: revision: avoid hitting packfiles when commits are in commit-graph commit-graph: split out function to search commit position revision: stop retrieving reference twice connected: do not sort input revisions revision: separate walk and unsorted flags