[9] RFR(XS) 8141140: Zero JVM fails to initialize after JDK-8078554

[Severin Gehwolf]

Hi,

Could somebody please review and sponsor this tiny change? It fixes a
Zero VM initialization problem happening after JDK-8078554.

My understanding is that AllocatePrefetchDistance received a new
constraint check with JDK-8078554 which now triggers for a Zero VM
since Zero didn't explicitly disable prefetching before.

Bug: https://bugs.openjdk.java.net/browse/JDK-8141140
webrev: http://cr.openjdk.java.net/~sgehwolf/webrevs/JDK-8141140/webrev.01/

Please note that this change depends on the change in [1] since Zero
does not build for me without it.

Thanks,
Severin

[1] http://mail.openjdk.java.net/pipermail/hotspot-dev/2015-November/020410.html