Reclassify recursive test case

Author: OlivierBlanvillain

tests/pos-deep-subtype/9849.scala renamed to tests/neg-custom-args/allow-deep-subtypes/9849.scala

@@ -1,4 +1,4 @@
-type *:[A, B] = A match
+type *:[A, B] = A match // error: Recursion limit exceeded.
   case (B *: x) => A
   case (x *: y) => x *: (B *: y)
   case _ => A *: B