Appease the c++14 buildbots

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@224304 91177308-0d34-0410-b5e6-96231b3b80d8

test/experimental/optional/optional.object/optional.object.observe/op_arrow.pass.cpp

@@ -25,7 +25,11 @@ using std::experimental::optional;
 
 struct X
 {
+#if _LIBCPP_STD_VER > 14
+    constexpr int test() const {return 3;}
+#else
     constexpr int test() {return 3;}
+#endif
 };
 
 #endif  // _LIBCPP_STD_VER > 11