Minor. Add more tests

compiler/testData/codegen/box/inlineClasses/kt38680bGeneric.kt

@@ -0,0 +1,20 @@
+// WITH_STDLIB
+// WORKS_WHEN_VALUE_CLASS
+// LANGUAGE: +ValueClasses, +GenericInlineClassParameter
+
+OPTIONAL_JVM_INLINE_ANNOTATION
+value class IC<T: String>(val s: T)
+
+interface IFoo<T> {
+    fun foo(x: T, s: String = "K"): String
+}
+
+interface IFoo2<T> : IFoo<T> {
+    fun bar(x: T) = foo(x)
+}
+
+class FooImpl : IFoo2<IC<String>> {
+    override fun foo(x: IC<String>, s: String): String = x.s + s
+}
+
+fun box(): String = FooImpl().bar(IC("O"))