RFR: Turn TestReferenceCAS into a standalone/no-testng test

[Roman Kennke]

TestReferenceCAS has been written (by me) as a TestNG test. I am not
sure why, but it's impractical when you want to debug this, e.g run
standalone, in debugger, etc. It also doesn't add any particular value.
This change proposes to turn the test into an ordinary main-test, and
also adds a comment how to run it, because I can't remember the magic
incantantion to get Unsafe accessible.

http://cr.openjdk.java.net/~rkennke/refcastest/webrev.00/

Ok?

Testing: TestReferenceCAS ;-)

Roman