Fix optional<char> test breakage

It seems GCC and clang disagree. Talked to mclow on IRC, disabling for now.

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@333317 91177308-0d34-0410-b5e6-96231b3b80d8

test/std/utilities/optional/optional.object/optional.object.ctor/deduct.pass.cpp

@@ -43,11 +43,15 @@ int main()
 
     {
 //  optional(const optional &);
+      // FIXME clang and GCC disagree about this!
+      // clang thinks opt is optional<optional<char>>, GCC thinks it's optional<char>.
+#if 0
     std::optional<char> source('A');
     std::optional opt(source);
     static_assert(std::is_same_v<decltype(opt), std::optional<std::optional<char>>>, "");
     assert(static_cast<bool>(opt) == static_cast<bool>(source));
     assert(*opt == *source);
+#endif
     }
 
 }