Allow data classes to inherit from other classes

#KT-10330 Fixed

compiler/testData/codegen/box/dataClasses/nonTrivialFinalMemberInSuperClass.kt

@@ -1,6 +1,3 @@
-// TODO: remove the suppression once data classes can have supertypes
-@file:Suppress("DATA_CLASS_CANNOT_HAVE_CLASS_SUPERTYPES")
-
 abstract class Base {
     final override fun toString() = "OK"
     final override fun hashCode() = 42

compiler/testData/codegen/box/dataClasses/nonTrivialMemberInSuperClass.kt

@@ -1,6 +1,4 @@
 // See KT-6206 Always generate hashCode() and equals() for data classes even if base classes have non-trivial analogs
-// TODO: remove the suppression once data classes can have supertypes
-@file:Suppress("DATA_CLASS_CANNOT_HAVE_CLASS_SUPERTYPES")
 
 abstract class Base {
     override fun toString() = "Fail"