Add test for #20482

tryNormalize used to not recursively check if tycon of applied type was normalizable,
this may be necessary in the case of an applied type dealiasing to a type lambda.

Fixes #20482

Author: EugeneFlesselle

tests/pos/i20482.scala

@@ -0,0 +1,16 @@
+trait WrapperType[A]
+
+case class Foo[A]()
+
+case class Bar[A]()
+
+type FooToBar[D[_]] = [A] =>> D[Unit] match {
+  case Foo[Unit] => Bar[A]
+}
+
+case class Test()
+object Test {
+  implicit val wrapperType: WrapperType[Bar[Test]] = new WrapperType[Bar[Test]] {}
+}
+
+val test = summon[WrapperType[FooToBar[Foo][Test]]]