add ultra-light classes/members that work without backend in simple cases

compiler/testData/asJava/ultraLightClasses/classModifiers.kt

@@ -0,0 +1,16 @@
+
+package pkg
+
+open class Open {
+  private class Private: Open {}
+  protected inner class Private2 {}
+  internal class StaticInternal {}
+}
+internal class OuterInternal {}
+private class TopLevelPrivate {}
+
+sealed class Season {
+    class Nested: Season()
+}
+
+sealed class SealedWithArgs(val a: Int)