RFR (XS): Fix Shenandoah argument checking on 32bit builds

[Aleksey Shipilev]

On 03/09/2017 03:49 PM, Roman Kennke wrote:
> This #ifdef _LP64 the part where we check for address space overflow
> when using the optimized ObjArrayChunkedTask.
> 
> On JDK8u, this also replaces the use of the (2-arg) UNSUPPORTED_OPTION
> with the 1-arg UNSUPPORTED_GC_OPTION (which was replaces with a 1-arg
> UNSUPPORTED_OPTION in JDK9).
> 
> http://cr.openjdk.java.net/~rkennke/fixargchecks32/webrev.00/

OK.

-Aleksey