[interpreter] Fix incorrect arg storage for arm softfp interpreter (#35643)

[interpreter] Fix incorrect arg storage for arm softfp interpreter (#35643)

In get_call_info, IS_HARD_FLOAT is checked to switch between using the FP registers and the GP registers. This was not done in arg_get_storage, which was always using the hard float registers. This would mean parameters to the native trampoline wouldn't get copied correctly, and return values would be incorrect as well.

I can't find a way to add this to tests, since no softfp test systems seem to be built. I'm working on testing the use cases I can think of on my softfp system just to be sure.

Any assignments to type RegTypeHFA were locked behind a IS_HARD_FLOAT check as well, so I think its safe to modify that case too.

Fixes mono/mono#14591