revset: stabilize repr of baseset initialized with a set

Cpython and pypy have different way to build and order set, so the result of
list(myset) is different. We work around this by using the sorted version of the
data when displaying a list.

This get pypy closer to pass test-revset.t.

mercurial/revset.py

@@ -2889,7 +2889,13 class baseset(abstractsmartset):
         d = {None: '', False: '-', True: '+'}[self._ascending]
         s = _formatsetrepr(self._datarepr)
         if not s:
-            s = repr(self._list)
+            l = self._list
+            # if _list has been built from a set, it might have a different
+            # order from one python implementation to another.
+            # We fallback to the sorted version for a stable output.
+            if self._ascending is not None:
+                l = self._asclist
+            s = repr(l)
         return '<%s%s %s>' % (type(self).__name__, d, s)
 
 class filteredset(abstractsmartset):

tests/test-revset.t

@@ -725,7 +725,7 Test opreand of '%' is optimized recursi
       ('symbol', '9')
       ('symbol', '5')))
   * set:
-  <baseset+ [8, 9, 2, 4]>
+  <baseset+ [2, 4, 8, 9]>
   2
   4
   8