Move blackBoxFile() testData to box/ directory

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

compiler/testData/codegen/box/enum/inclassobj.kt

@@ -0,0 +1,15 @@
+fun box() = if(Context.operatingSystemType == Context.OsType.OTHER) "OK" else "fail"
+
+public class Context
+{
+        class object
+        {
+                public enum class OsType {
+                        LINUX;
+                        OTHER
+                }
+
+                public val operatingSystemType: OsType
+                        get() = OsType.OTHER
+        }
+}