Test for abstract function in java enum.

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

@@ -0,0 +1,17 @@
+// FILE: A.java
+public enum A {
+
+    ENTRY {
+        public String s() {
+            return "s";
+        }
+    };
+    public abstract String s();
+}
+
+// FILE: test.kt
+package test
+
+fun main() {
+    A.ENTRY.s(): String?
+}