Remove some legacy codegen tests, move some to generated

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

@@ -0,0 +1,14 @@
+// WITH_RUNTIME
+
+enum class State {
+    O,
+    K
+}
+
+fun box(): String {
+    val field = State::class.java.getField("O")
+    val className = field.get(null).javaClass.name
+    if (className != "State") return "Fail: $className"
+
+    return "${State.O.name}${State.K.name}"
+}