resolve: split test Part of test-resolve.t is split into multiple tests to create an injection point for new tests that will be added in subsequent patches.

resolve: use early continue and deindent

mergestate: consistently set variables to None Some code branches and exceptional circumstances such as empty mergestate files could result in mergestate._local and mergestate._other not being defined or reset to None. These variables are now correctly set to None when they should be.

changegroup: refactor outgoing logic into a function Extensions that add to bundle2 will want to know which commits are outgoing so they can bundle data that is appropriate to those commits. This moves the logic for figuring that out to a separate function so extensions can do the same computation.

bundle2: fix bundle2 pulling all revs on empty pulls When bundle2 was enabled, if hg pull had no commits to pull, it would print 'no changes found' and then download the entire repository from the server. This was caused by heads and common being set to None, which gets treated as heads=cl.heads() and common=[nullid], which means download the entire repo. Pulling bundles without a changegroup is a valid use case (like if we're just updating bookmarks), so this modifes the bundle code to allow not adding changegroups.

exchange: fix bad indentation Those two lines where double indented for no good reasons.

exchange: propagate arguments to the _getbundleextrapart function The arguments was wrongly propagated (again).

bundle2: fix configuration name mismatch During pulls bundle2 was checking server.bundle2, but during pushes it was checking experimental.bundle2. This makes them both experimental.bundle2.