K2: Imitate K1 behavior for case of captured types with a raw supertype

See the comments in the code, but mostly the motivation is that once
it was decided to stick with such a legacy thing as raw types,
we are ok with some corner-cases hacks for them
(if there are not too many of them) and they don't break anything
when there are no raw types in the code.

^KT-56616 Fixed

core/descriptors/src/org/jetbrains/kotlin/types/checker/ClassicTypeSystemContext.kt

@@ -158,6 +158,10 @@ interface ClassicTypeSystemContext : TypeSystemInferenceExtensionContext, TypeSy
         return this is RawType
     }
 
+    override fun KotlinTypeMarker.convertToNonRaw(): KotlinTypeMarker {
+        error("Is not expected to be called in K1")
+    }
+
     override fun FlexibleTypeMarker.upperBound(): SimpleTypeMarker {
         require(this is FlexibleType, this::errorMessage)
         return this.upperBound