[committed] Convert xstormy16 to LRA

[Paul Koning]

> On May 1, 2023, at 7:37 PM, Roger Sayle <roger@nextmovesoftware.com> wrote:
> 
> ...
> The shiftsi.cc regression on xstormy16 is fixed by adding
> -fno-split-wide-types.
> In fact, if all the regression tests pass, I'd suggest that
> flag_split_wide-types = false
> should be the default on xstormy16 now that we've moved to LRA.  And if this
> works for xstormy16, it might be useful to other targets for the LRA
> transition;
> it's a difference in behaviour between reload and LRA that could potentially
> affect multiple targets.

Is there documentation for that flag?  

	paul