detail::basic_string initialization

[malachib]

There is some ambiguity as to whether default construction for detail::basic_string actually initializes an empty string or not.

Certainly std::string does. However, in our embedded space it's more appropriate to lean towards totally uninitialized. It's been a while so I am not sure but it seems like that's what we do overall.

All that being said, it would be nice to have something like an in_place_t to really truly initialize as an empty string.

This might apply also to its allocated_array relatives such as vector, etc.

Looks like we have some ancient DEBT in dynamic_array_base which does force size to 0. Bummer