Avoid some GCC 10.X warnings in HotSpot

[Kim Barrett]

> On Jul 8, 2020, at 8:35 AM, Koichi Sakata <sakatakui at oss.nttdata.com> wrote:
> 
> I fixed my patch because it had unnecessary code that was pointed before.
> I would appreciate if anyone could sponsor this patch.

What about this unaddressed comment?

> On Jul 7, 2020, at 10:36 AM, Kim Barrett <kim.barrett at oracle.com> wrote:
> However, the first two elements of _body are used by identity_hash().
> That seems like a possible reason to force initialization of both
> elements, which currently isn't done for length == 1.  But maybe it
> doesn't matter that identity_hash isn't consistent between processes,
> in which case forcing the initialization of _body[0] also shouldn't
> be needed.

I think it’s a waste to initialize _body[0] or a bug to not initialize _body[1].
I’ve no idea which.