Refine ClassDescriptor::isCommonFinalClass definition

Do not treat annotations as final classes as they are not final in Java

 #KT-20776 Fixed

compiler/testData/diagnostics/tests/j+k/annotationsInheritance.kt

@@ -0,0 +1,19 @@
+// FILE: MyAnnotation.java
+public @interface MyAnnotation {
+}
+// FILE: MyAnnoClass.java
+public class MyAnnoClass implements MyAnnotation {
+//...
+}
+
+// FILE: main.kt
+
+val ann: MyAnnotation = MyAnnoClass()
+
+fun foo(x: MyAnnoClass) {
+    bar(x)
+}
+
+fun bar(y: MyAnnotation) {
+    y.hashCode()
+}