RFR(XS): 8130676: [TESTBUG] aix: Port CreateCoreDumpOnCrash added in 8078121

[Lindenmaier, Goetz]

Hi,

This test  does Utils.getUnsafe().getInt(0) effectively reading from address '0'
to cause a crash.
Unfortunately this is possible on aix, as the zero page is not write protected.

Fix: use putInt() instead.

Please review this tiny change.  I please need a sponsor.
http://cr.openjdk.java.net/~goetz/webrevs/8130676-crshTst/webrev.01/

Best regards,
  Goetz.