[Tests] Migrate backend-independent tests from native to compiler/testData.

^KT-65979

compiler/testData/codegen/box/enum/test1.kt

@@ -0,0 +1,18 @@
+/*
+ * Copyright 2010-2018 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license
+ * that can be found in the LICENSE file.
+ */
+// WITH_STDLIB
+
+import kotlin.test.*
+
+enum class Zzz(val zzz: String, val x: Int) {
+    Z1("z1", 1),
+    Z2("z2", 2)
+}
+
+fun box(): String {
+    assertEquals("z12", Zzz.Z1.zzz + Zzz.Z2.x)
+
+    return "OK"
+}