trace_division: fix comma prefix

This way, the ',' behaves like the old '/'. This change is introduced to
support division on multiple lines.

my2to3/fixers/fix_trace_division.py

@@ -38,6 +38,9 @@ class FixTraceDivision(lib2to3.fixer_base.BaseFix):
 
   def transform(self, node, results):
     lineno = node.get_lineno()
+    comma = lib2to3.fixer_util.Comma()
+    comma.prefix = prefix=node.children[1].prefix
+
     node.replace(
         lib2to3.fixer_util.Call(
             lib2to3.fixer_util.Name("division_traced"),
@@ -45,7 +48,7 @@ class FixTraceDivision(lib2to3.fixer_base.BaseFix):
                 lib2to3.fixer_util.Number(self.ids[lineno]),
                 lib2to3.fixer_util.Comma(),
                 node.children[0].clone(),
-                lib2to3.fixer_util.Comma(),
+                comma,
                 node.children[2].clone(),
             ),
             prefix=node.prefix))