Make enum classes comparable

#KT-3727 Fixed

js/js.translator/testData/enum/cases/enumIsComparable.kt

@@ -0,0 +1,24 @@
+package foo
+
+enum class A {
+    one
+    two
+}
+
+fun box(): String {
+    val x = A.one.compareTo(A.two)
+    if (x != -1) return "Fail cmp(one, two) = $x"
+    val y = A.two.compareTo(A.one)
+    if (y != 1) return "Fail cmp(two, one) = $y"
+
+    if (!(A.one < A.two)) return "Fail !(one < two)"
+    if (A.one >= A.two) return "Fail one >= two"
+
+    if (!(A.two > A.one)) return "Fail !(two > one)"
+    if (A.two <= A.one) return "Fail two <= one"
+
+    val z = A.one.compareTo(A.one)
+    if (z != 0) return "Fail cmp(one, one) = $z"
+
+    return "OK"
+}

js/js.translator/testData/enum/cases/standardMethods.kt

@@ -23,6 +23,7 @@ fun box(): String {
 
     val ok2 = Simple.valueOf("OK")
     if (!ok2.equals(ok)) return "ok2 not equal ok"
+    if (ok2.hashCode() != ok.hashCode()) return "hash(ok2) not equal hash(ok)"
     if (!ok2.identityEquals(ok)) return "ok2 not identity equal ok"
 
 
@@ -33,6 +34,7 @@ fun box(): String {
     if (A.c.toString() != "c") return "A.c.toString() != c, it: ${A.c.toString()}"
     if (A.valueOf("b") != A.b) return "A.valueOf('b') != A.b"
     if (A.a == A.b) return "A.a == A.b"
+    if (A.a.hashCode() == A.b.hashCode()) return "hash(A.a) == hash(A.b)"
 
     if (A.a.name() != "a") return "A.a.name() != a, it: ${A.a.name()}"
     if (A.b.name() != "b") return "A.b.name() != b, it: ${A.b.name()}"