Need reviewer - add test to make sure xshare:dump always works

[Kelly O'Hair]

Addition of a testcase to our JPRT system to make sure -Xshare:dump and
misc command line options work (i.e. don't create non-zero exit conditions :^)
on every build of hotspot.

6839151: Add a JPRT default test of -Xshare:dump when new hotspot is built
http://cr.openjdk.java.net/~ohair/jdk7/6839151-hotspot-xshare-test/webrev/

This could catch some of the problems seen with class data sharing in the
past, and allows for adding future command line checks.

-kto