RFR (S): 8240590: Add MemRegion::destroy_array to complement introduced create_array

[Thomas Schatzl]

Hi all,

   can I have reviews for this small change that introduces a 
MemRegion::destroy_array() method to complement the recently introduced 
MemRegion::create_array().

CR:
https://bugs.openjdk.java.net/browse/JDK-8240590
Webrev:
http://cr.openjdk.java.net/~tschatzl/8240590/webrev/
Testing:
hs-tier1-5

Thanks,
   Thomas