Make enum classes comparable

#KT-3727 Fixed

compiler/testData/codegen/boxWithStdlib/enum/sortEnumEntries.kt

@@ -0,0 +1,16 @@
+import Game.*
+
+enum class Game {
+    ROCK
+    PAPER
+    SCISSORS
+    LIZARD
+    SPOCK
+}
+
+fun box(): String {
+    val a = array(LIZARD, SCISSORS, SPOCK, ROCK, PAPER)
+    a.sort()
+    val str = a.joinToString(" ")
+    return if (str == "ROCK PAPER SCISSORS LIZARD SPOCK") "OK" else "Fail: $str"
+}

compiler/testData/diagnostics/tests/enum/overrideFinalEnumMethods.kt

@@ -4,6 +4,8 @@ enum class E {
     <!OVERRIDING_FINAL_MEMBER!>override<!> fun name(): String = "lol"
     <!OVERRIDING_FINAL_MEMBER!>override<!> fun ordinal(): Int = 0
 
+    <!OVERRIDING_FINAL_MEMBER!>override<!> fun compareTo(other: E) = -1
+
     <!OVERRIDING_FINAL_MEMBER!>override<!> fun equals(other: Any?) = true
     <!OVERRIDING_FINAL_MEMBER!>override<!> fun hashCode() = -1
 }

compiler/testData/diagnostics/tests/enum/overrideFinalEnumMethods.txt

@@ -2,6 +2,7 @@ package
 
 internal final enum class E : kotlin.Enum<E> {
     private constructor E()
+    public open override /*1*/ fun compareTo(/*0*/ other: E): kotlin.Int
     public open override /*1*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
     public open override /*1*/ fun hashCode(): kotlin.Int
     public open override /*1*/ fun name(): kotlin.String
@@ -10,6 +11,7 @@ internal final enum class E : kotlin.Enum<E> {
     
     public enum entry ENTRY : E {
         private constructor ENTRY()
+        public open override /*1*/ /*fake_override*/ fun compareTo(/*0*/ other: E): kotlin.Int
         public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
         public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
         public open override /*1*/ /*fake_override*/ fun name(): kotlin.String
@@ -18,6 +20,7 @@ internal final enum class E : kotlin.Enum<E> {
         
         public class object <class-object-for-ENTRY> : E.ENTRY {
             private constructor <class-object-for-ENTRY>()
+            public open override /*1*/ /*fake_override*/ fun compareTo(/*0*/ other: E): kotlin.Int
             public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
             public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
             public open override /*1*/ /*fake_override*/ fun name(): kotlin.String