Remove some legacy codegen tests, move some to generated

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

@@ -0,0 +1,27 @@
+// WITH_RUNTIME
+// FULL_JDK
+
+import java.lang.reflect.Modifier
+
+enum class En {
+    Y
+}
+
+fun box(): String {
+    val klass = En::class.java
+    val superclass = klass.superclass.name
+    if (superclass != "java.lang.Enum") "Fail superclass: $superclass"
+
+    val enumModifiers = klass.modifiers
+    if ((enumModifiers and 0x4000) == 0) return "Fail ACC_ENUM on class"
+    if ((enumModifiers and Modifier.FINAL) == 0) return "Fail FINAL on class"
+
+    val entry = klass.getField("Y")
+    val entryModifiers = entry.modifiers
+    if ((entryModifiers and 0x4000) == 0) return "Fail ACC_ENUM on entry"
+    if ((entryModifiers and Modifier.FINAL) == 0) return "Fail FINAL on entry"
+    if ((entryModifiers and Modifier.STATIC) == 0) return "Fail FINAL on entry"
+    if ((entryModifiers and Modifier.PUBLIC) == 0) return "Fail FINAL on entry"
+
+    return "OK"
+}