Assert that reference annotation argument is always an enum value

Rename JavaReferenceAnnotationArgument on that occasion to
JavaEnumValueAnnotationArgument. Also add a test on a nested enum annotation
argument

compiler/testData/loadJava/compiledJava/annotations/NestedEnumArgument.java

@@ -0,0 +1,14 @@
+package test;
+
+public class NestedEnumArgument {
+    public enum E {
+        FIRST
+    }
+
+    @interface Anno {
+        E value();
+    }
+
+    @Anno(E.FIRST)
+    void foo() {}
+}

compiler/testData/loadJava/compiledJava/annotations/NestedEnumArgument.txt

@@ -0,0 +1,33 @@
+package test
+
+public open class NestedEnumArgument {
+    public constructor NestedEnumArgument()
+    test.NestedEnumArgument.Anno(value = E.FIRST: test.NestedEnumArgument.E) public/*package*/ open fun foo(): kotlin.Unit
+
+    public/*package*/ final annotation class Anno : kotlin.Annotation {
+        public/*package*/ constructor Anno(/*0*/ value: test.NestedEnumArgument.E)
+        public abstract fun value(): test.NestedEnumArgument.E
+    }
+
+    public final enum class E : kotlin.Enum<test.NestedEnumArgument.E> {
+        private constructor E()
+        public final override /*1*/ /*fake_override*/ fun name(): kotlin.String
+        public final override /*1*/ /*fake_override*/ fun ordinal(): kotlin.Int
+
+        public enum entry FIRST : test.NestedEnumArgument.E {
+            private constructor FIRST()
+            public final override /*1*/ /*fake_override*/ fun name(): kotlin.String
+            public final override /*1*/ /*fake_override*/ fun ordinal(): kotlin.Int
+
+            public class object <class-object-for-FIRST> : test.NestedEnumArgument.E.FIRST {
+                private constructor <class-object-for-FIRST>()
+                public final override /*1*/ /*fake_override*/ fun name(): kotlin.String
+                public final override /*1*/ /*fake_override*/ fun ordinal(): kotlin.Int
+            }
+        }
+
+        // Static members
+        public final /*synthesized*/ fun valueOf(/*0*/ value: kotlin.String): test.NestedEnumArgument.E
+        public final /*synthesized*/ fun values(): kotlin.Array<test.NestedEnumArgument.E>
+    }
+}