Minor, add test on bound reference to enum entry member

compiler/testData/codegen/box/callableReference/bound/enumEntryMember.kt

@@ -0,0 +1,13 @@
+enum class E {
+    A, B;
+
+    fun foo() = this.name
+}
+
+fun box(): String {
+    val f = E.A::foo
+    if (f() != "A") return "Fail 1: ${f()}"
+    if (f != E.B::foo) return "Fail 2"
+
+    return "OK"
+}