changegroup: don't try to prune manifest nodes if not ellipses

In non-ellipses case, the number of manifest nodes can be very big, and finding
whether one of them can be pruned or not is very costly. For each node, we try
to find the rev and the linkrev, which is expensive.

Sending bit more manifest nodes seems better and much faster here. On our
internal repository, this saves around 5 seconds on `hg tracked --addinclude
<some_path>` on a narrow repo with ellipses disabled.

Differential Revision: https://phab.mercurial-scm.org/D5782

mercurial/changegroup.py

@@ -1073,6 +1073,11 b' class cgpacker(object):'
                 # because of narrow clones). Do this even for the root
                 # directory (tree=='')
                 prunednodes = []
+            elif not self._ellipses:
+                # In non-ellipses case and large repositories, it is better to
+                # prevent calling of store.rev and store.linkrev on a lot of
+                # nodes as compared to sending some extra data
+                prunednodes = nodes.copy()
             else:
                 # Avoid sending any manifest nodes we can prove the
                 # client already has by checking linkrevs. See the