Fix broken isEnumClassObject methods

Out of three methods, two were incorrect

compiler/testData/codegen/box/classes/classObjectNotOfEnum.kt

@@ -0,0 +1,8 @@
+class A {
+    class object {
+        fun values() = "O"
+        fun valueOf() = "K"
+    }
+}
+
+fun box() = A.values() + A.valueOf()

compiler/testData/loadJava/compiledJava/static/Enum.java

@@ -7,9 +7,11 @@ public enum Enum {
 
     public static class Nested {
         void foo() {}
+        void values() {}
     }
 
     public class Inner {
         void bar() {}
+        void valueOf(String s) {}
     }
 }

compiler/testData/loadJava/compiledJava/static/Enum.txt

@@ -17,10 +17,12 @@ public final enum class Enum : jet.Enum<test.Enum> {
     public open inner class Inner : java.lang.Object {
         public constructor Inner()
         public/*package*/ open fun bar() : Unit
+        public/*package*/ open fun valueOf(/*0*/ p0 : jet.String?) : Unit
     }
     
     public open class Nested : java.lang.Object {
         public constructor Nested()
         public/*package*/ open fun foo() : Unit
+        public/*package*/ open fun values() : Unit
     }
 }