Quantify code-size cost

[gnzlbg]

Zach Laine wrote in the std-proposals thread:

I really want to see some real numbers on this. Please instantiate several kinds of static_vector-like things (hand-rolled struct consisting of std::array + size_t, static_vector, your implementation, etc.) in scenarios where you would expect there to be larger code size, and let's see some assembly, or at least relative counts of instructions.