Move blackBoxFile() testData to box/ directory

Delete all test methods (and empty test classes), since they'll be
auto-generated

compiler/testData/codegen/box/classes/kt1134.kt

@@ -0,0 +1,7 @@
+public class SomeClass() : java.lang.Object() {
+}
+
+public fun box():String {
+    System.out?.println(SomeClass().getClass())
+    return "OK"
+}