Rewrite ir interpreter's dump tests to box

Box tests will check the correctness of interpreter, meantime
by dumped ir we can understand that expression was folded.

compiler/testData/ir/loweredIr/interpreter/enumName.kt

@@ -6,3 +6,10 @@ const val name1 = EnumClass.OK.name
 const val name2 = EnumClass.VALUE.name
 const val name3 = EnumClass.anotherValue.name
 const val name4 = EnumClass.WITH_UNDERSCORE.name
+
+fun box(): String {
+    if (name2 != "VALUE") return "Fail 1"
+    if (name3 != "anotherValue") return "Fail 2"
+    if (name4 != "WITH_UNDERSCORE") return "Fail 3"
+    return name1
+}