[FE] Prohibit inheritance of sealed classes in different module

KT-20423

compiler/testData/diagnostics/tests/sealed/interfaces/inheritorInDifferentModule.fir.kt

@@ -0,0 +1,17 @@
+// ISSUE: KT-20423
+// !LANGUAGE: +SealedInterfaces +FreedomForSealedClasses
+
+// MODULE: m1
+// FILE: a.kt
+package a
+
+sealed interface Base
+
+interface A : Base
+
+// MODULE: m2(m1)
+// FILE: b.kt
+
+package a
+
+interface B : Base