[FIR/AA decompiler] Add tests for sealed interfaces

^KT-62895

analysis/decompiled/decompiler-to-file-stubs/testData/clsFileStubBuilder/SealedInterface/SealedInterface.kt

@@ -0,0 +1,7 @@
+// FIR_IDENTICAL
+package test
+
+sealed interface SealedInterface {
+    class Nested : SealedInterface
+    object Top : SealedInterface
+}

analysis/decompiled/decompiler-to-file-stubs/testData/clsFileStubBuilder/SealedInterface/SealedInterface.txt

@@ -0,0 +1,30 @@
+PsiJetFileStubImpl[package=test]
+  PACKAGE_DIRECTIVE
+    REFERENCE_EXPRESSION[referencedName=test]
+  IMPORT_LIST
+  CLASS[classId=test/SealedInterface, fqName=test.SealedInterface, isEnumEntry=false, isInterface=true, isLocal=false, isTopLevel=true, name=SealedInterface, superNames=[]]
+    MODIFIER_LIST[public]
+    CLASS_BODY
+      CLASS[classId=test/SealedInterface.Nested, fqName=test.SealedInterface.Nested, isEnumEntry=false, isInterface=false, isLocal=false, isTopLevel=false, name=Nested, superNames=[SealedInterface]]
+        MODIFIER_LIST[public final]
+        PRIMARY_CONSTRUCTOR[fqName=null, hasBody=false, isDelegatedCallToThis=false, isExtension=false, isTopLevel=false, name=Nested]
+          MODIFIER_LIST[public]
+          VALUE_PARAMETER_LIST
+        SUPER_TYPE_LIST
+          SUPER_TYPE_ENTRY
+            TYPE_REFERENCE
+              USER_TYPE
+                USER_TYPE
+                  REFERENCE_EXPRESSION[referencedName=test]
+                REFERENCE_EXPRESSION[referencedName=SealedInterface]
+        CLASS_BODY
+      OBJECT_DECLARATION[classId=test/SealedInterface.Top, fqName=test.SealedInterface.Top, isCompanion=false, isLocal=false, isObjectLiteral=false, isTopLevel=false, name=Top, superNames=[SealedInterface]]
+        MODIFIER_LIST[public]
+        SUPER_TYPE_LIST
+          SUPER_TYPE_ENTRY
+            TYPE_REFERENCE
+              USER_TYPE
+                USER_TYPE
+                  REFERENCE_EXPRESSION[referencedName=test]
+                REFERENCE_EXPRESSION[referencedName=SealedInterface]
+        CLASS_BODY