Move test to pending

The underlying problem on MacOS/Windows remains:

We have a class `B` and an object `b` in the same scope.
We used to get a conflict on `B$/b$` because we created
an empty companion object for `B`. Now we get a conflict
for `B/b`, because the `b` object creates to classes:
`b.class` an `b$.class` and `b.class` clashes with `B.class`.

Author: odersky

tests/run/t920.scala renamed to tests/pending/run/t920.scala

@@ -17,4 +17,9 @@ object Test {
   def main(args : Array[String]) : Unit = {
     b.initialize;
   }
+  class XYZ
 }
+
+
+
+