Add test for scala.Phantom self type

Author: nicolasstucki

tests/run/phantom-self-1.check

@@ -0,0 +1,14 @@
+object Test {
+    def main(args: Array[String]): Unit = {
+      Boo.any
+      Boo.any2
+    }
+}
+
+object Boo extends Phantom with T
+
+trait T { self: Phantom =>
+  type X = self.Any
+  def any: X = self.assume
+  def any2: X = assume
+}