RFR (S): 8181787: Remove Solaris SPARC GCC code

[Kim Barrett]

> On Jun 8, 2017, at 11:06 AM, Erik Österlund <erik.osterlund at oracle.com> wrote:
> 
> Hi,
> 
> The only supported way of building OpenJDK on Solaris is via the studio compiler. However, there are unsupported code paths that are enabled only if _GNU_SOURCE is defined. This might be problematic for multiple reasons. Checking for _GNU_SOURCE does not check for GCC, it checks whether the standard library is the GNU standard library. Most importantly, the code has been bit rotting and e.g. the inline assembly for atomic seems to have flaws. Since we never test the correctness of these code paths, I propose to remove this unsupported code.
> 
> Bug: https://bugs.openjdk.java.net/browse/JDK-8181787
> 
> Webrev: http://cr.openjdk.java.net/~eosterlund/8181787/webrev.00/
> 
> Testing: JPRT
> 
> Will need a sponsor.
> 
> Thanks,
> /Erik

The change to os::readdir in os_solaris.inline.hpp is a bit outside
the remit for this bug.  But it looks fine.

Looks good.  Remember to update copyrights.

I can sponsor.