[C++][C++17] is_literal_type deprecated

std::is_literal_type is deprecated.

Reason:
Deprecated std::is_literal_type in C++17

Quote:
The is_literal type trait offers negligible value to generic code, as what is really needed is the ability to know that a specific construction would produce constant initialization.

The core term of a literal type having at least one constexpr constructor is too weak to be used meaningfully.

Reference
http://en.cppreference.com/w/cpp/concept/LiteralType