Introduce KAnnotatedElement and val annotations: List<Annotation>

compiler/testData/codegen/boxWithStdlib/reflection/annotations/simpleClassAnnotation.kt

@@ -0,0 +1,8 @@
+annotation(retention = AnnotationRetention.RUNTIME) class Simple(val value: String)
+
+@Simple("OK")
+class A
+
+fun box(): String {
+    return (A::class.annotations.single() as Simple).value
+}