Merge boxWithStdlib testData into box, delete BoxWithStdlib test

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

@@ -0,0 +1,11 @@
+// WITH_REFLECT
+
+@Retention(AnnotationRetention.RUNTIME)
+annotation class Simple(val value: String)
+
+@Simple("OK")
+class A
+
+fun box(): String {
+    return (A::class.annotations.single() as Simple).value
+}