Move <optional> into include/experimental, and into the std::experimental namespace, since it's not part of C++14, but of an upcoming TS

llvm-svn: 194867

libcxx/test/utilities/optional/optional.object/optional.object.observe/bool.pass.cpp

@@ -11,19 +11,21 @@
 
 // constexpr explicit optional<T>::operator bool() const noexcept;
 
-#include <optional>
+#include <experimental/optional>
 #include <type_traits>
 #include <cassert>
 
 int main()
 {
 #if _LIBCPP_STD_VER > 11
+    using std::experimental::optional;
+
     {
-        constexpr std::optional<int> opt;
+        constexpr optional<int> opt;
         static_assert(!opt, "");
     }
     {
-        constexpr std::optional<int> opt(0);
+        constexpr optional<int> opt(0);
         static_assert(opt, "");
     }
 #endif  // _LIBCPP_STD_VER > 11