RFR: Fix object initialization in C2

[Roman Kennke]

Am Mittwoch, den 07.12.2016, 09:55 +0100 schrieb Roland Westrelin:
> > http://cr.openjdk.java.net/~rkennke/obj-init/webrev.00/
> 
> That looks good to me.

Thanks. I pushed it.

Turns out that we're saved by the prefetch-reserve in
ThreadLocalAllocationBuffer: it always allocates a few words more than
necessary and thus we're never jumping off the cliff. Lucky us :-)

Roman