RFR: 8178813: Add test for G1 pre-barrier on dereference of weak JNI handles

[Per Liden]

On 2017-05-11 01:39, Kim Barrett wrote:
[...]
> It made it easier to test the test, by backing out the fixes being tested and
> verifying both failure modes.  But I agree it does uglify the test itself, and
> now that we expected it to always pass, that’s more important.  So fixed.
>
> New webrevs:
> full: http://cr.openjdk.java.net/~kbarrett/8178813/hotspot.02/
> incr: http://cr.openjdk.java.net/~kbarrett/8178813/hotspot.02.inc/
>

Still looks good.

cheers,
Per