Please review JDK-8059811

[Marcus Lagergren]

This is 

1) Optimistic types moving to a documented option in jjs -help
2) Optimistic types being default off for 8u40 (it is still left on in this that goes into 9 - will flip the flag at backport)
3) Support for testing in both optimistic and non optimistic mode for all the unit tests with ‘ant test’. This will be live in both 8u40 and 9 (but with different defaults - same tests though) to avoid bit rot of the non-optimistic functionality as long as it exists.

Please give me reviews. Ant test passes with both configurations after Hannes fixing JDK-8059938

The webrev is here: http://cr.openjdk.java.net/~lagergren/8059811.3/

/M