Restored accidentally deleted test code.

Author: odersky

tests/pos/subtyping.scala

@@ -1,3 +1,9 @@
+class A {
+  def test1(): Unit = {
+    implicitly[this.type <:< this.type]
+    implicitly[this.type <:< A]
+  }
+}
 object test {
 
   class B