backend/tests: Add blackbox tests from Kotlin JVM

Added tests from testData/codegen/box directory. There are blackbox tests
in other directories and they are to be added.

backend.native/tests/external/codegen/blackbox/annotations/fileClassWithFileAnnotation.kt

@@ -0,0 +1,14 @@
+// TODO: muted automatically, investigate should it be ran for JS or not
+// IGNORE_BACKEND: JS
+
+// WITH_RUNTIME
+
+@file:StringHolder("OK")
+@file:JvmName("FileClass")
+
+@Target(AnnotationTarget.FILE)
+@Retention(AnnotationRetention.RUNTIME)
+public annotation class StringHolder(val value: String)
+
+fun box(): String =
+        Class.forName("FileClass").getAnnotation(StringHolder::class.java)?.value ?: "null"