RFA: Skip largefile PCH test on Solaris 10 x86

[Eric Botcazou]

> As detailed in PR 14940, PCH on Solaris 10 x86 doesn't work very well:
> there doesn't seem to be any way to get consistent addresses from
> mmap.  Small PCH tests work, but big ones don't.  In practice, PCH is
> probably not useful on this platform, but I'm not sure if we have a
> good way to totally disable it.

Note that PR 14940 is originally about SPARC/Solaris.

-- 
Eric Botcazou