[Bug target/53513] [SH] Add support for fschg and fpchg insns and improve fenv support

[olegendo at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=53513

--- Comment #34 from Oleg Endo <olegendo at gcc dot gnu.org> ---
Test run for 

  -m2e -ml, -m2a -mb, -m2a-single -mb, -m4-single-ml

has finished and shows no new failures (except the ISR stuff).