Merge boxWithStdlib testData into box, delete BoxWithStdlib test

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

@@ -0,0 +1,16 @@
+// WITH_REFLECT
+
+import kotlin.test.assertEquals
+
+@Retention(AnnotationRetention.RUNTIME)
+annotation class Anno
+
+fun box(): String {
+    val a = Anno::class.annotations
+
+    if (a.size != 1) return "Fail 1: $a"
+    val ann = a.single() as? Retention ?: return "Fail 2: ${a.single()}"
+    assertEquals(AnnotationRetention.RUNTIME, ann.value)
+
+    return "OK"
+}