[IR] Split implementation of DataClassMembersGenerator to IR based and descriptor based

compiler/testData/ir/irText/firProblems/MultiList.fir.kt.txt

@@ -14,7 +14,7 @@ data class Some<T : Any?> {
   }
 
   fun copy(value: T = <this>.#value): Some<T> {
-    return Some<Any>(value = value)
+    return Some<T>(value = value)
   }
 
   override operator fun equals(other: Any?): Boolean {