[PATCH] Fix tst-setcontext9 for optimized small stacks.

[Florian Weimer]

* Andreas Schwab:

> On Sep 26 2018, Carlos O'Donell <carlos@redhat.com> wrote:
>
>> Does it run out of stack?
>
> Definitely.
>
> Andreas.
>
> 	[BZ #23717]
> 	* stdlib/tst-setcontext9.c (f1a): Make st2 static.
> 	(do_test): Make st1 static.

I'm happy to report that this fixes powerpc64le for me.  The change
looks reasonable.  Maybe you coulkd mention somewhere (in the ChangeLog
entry or the commit message) that this is to reduce stack usage and
avoid stack overflows.

Thanks,
Florian