py3: alias long to int and xrange to range in test-ancestor.py on Python 3

tests/test-ancestor.py

@@ -13,10 +13,15 b' from mercurial import ('
     ancestor,
     debugcommands,
     hg,
+    pycompat,
     ui as uimod,
     util,
 )
 
+if pycompat.ispy3:
+    long = int
+    xrange = range
+
 def buildgraph(rng, nodes=100, rootprob=0.05, mergeprob=0.2, prevprob=0.7):
     '''nodes: total number of nodes in the graph
     rootprob: probability that a new node (not 0) will be a root