[Bug target/85667] (x86_64) ms_abi rules aren't followed when returning short structs with float values

[mateuszb at poczta dot onet.pl]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=85667

--- Comment #6 from mateuszb at poczta dot onet.pl ---
Now it is fixed for 64-bit GCC 9.
For 32-bit GCC 9 it is not fixed (return goes to st(0)).