[libc++] Fix compilation error on platforms that don't implement std::tm

[libc++] Fix compilation error on platforms that don't implement std::tm

Instead of mentioning tm directly in the definition of __convert_to_tm,
take it as a template argument. As a fly-by also fix incorrect Lit feature
(should have been no-localization instead of libcpp-has-no-localization).

Differential Revision: https://reviews.llvm.org/D133490