Swap arguments to _mm*_{min,max}_ps

[kalenedrael]

std::min and std::max return their second argument if either argument is NAN, while the intrinsics return the first argument. This brings xsimd::{min,max} in line with std::{min,max}, at least on x86.

[serge-sans-paille]

Thanks! Could you add a test case for this?

[kalenedrael]

Added a test case. I'm not entirely clear on how the architecture-specific tests work though, so let me know if something else needs to be added.

[serge-sans-paille]

Added a test case. I'm not entirely clear on how the architecture-specific tests work though, so let me know if something else needs to be added.

That's fine, thanks. I'll do the portage to other architectures if needs be!

[kalenedrael]

Correction for potential future readers: The first comment has it backwards - std::min and std::max return their first argument if either argument is NAN, while the intrinsics return their second argument.