narrow: move remaining narrow-limited dirstate walks to core In most places we now filter at a higher level (the context object), but there are few places that relied on the dirstate walk to be filtered by the narrowspec. The important cases are those used by `hg add` and `hg addremove`. This patch updates them to pass in a matcher instead of relying on the dirstate to do the filtering. The dirstate filtering is also dropped in narrowdirstate.py. Not always filtering in the dirstate should be useful for a future `hg status --include-outside-narrow` option. These places now end up doing an unrestricted dirstate walk after this patch: * debugfileset * perfwalk * sparse (but restricted to sparse config) * largefiles I'll let anyone who cares about these cases adapt them to work with narrow if necessary. Differential Revision: https://phab.mercurial-scm.org/D4901

Integration with the share extension needs improvement. Right now
we've seen some odd bugs.

Address commentary in manifest.excludedmanifestrevlog.add -
specifically we should improve the collaboration with core so that
add() never gets called on an excluded directory and we can improve
the stand-in to raise a ProgrammingError.

Reason more completely about rename-filtering logic in
narrowfilelog. There could be some surprises lurking there.

Formally document the narrowspec format. For bonus points, unify with the
server-specified narrowspec format.

narrowrepo.setnarrowpats() or narrowspec.save() need to make sure
they're holding the wlock.

The follinwg places do an unrestricted dirstate walk (including files outside the
narrowspec). Some of them should perhaps not do that.

 * debugfileset
 * perfwalk
 * sparse (but restricted to sparse config)
 * largefiles