RFR: 8062206: Remove unusable G1RSLogCheckCardTable command line argument

[Thomas Schatzl]

Hi Kim,

On Mon, 2014-11-03 at 13:41 -0500, Kim Barrett wrote:
> Please review this removal of conditional code that appears to have never
> worked and doesn't have an apparent repair.
> 
> Webrev:
> http://cr.openjdk.java.net/~kbarrett/8062206/webrev/
> 
> Bug:
> https://bugs.openjdk.java.net/browse/JDK-8062206
[...]
> 
> Removed from G1RemSet::updateRS() the assertion that all cards are clean after
> remembered set updating.  This "invariant" hasn't held during the entire life
> of G1 in the hotspot repository.  Presently, cards for young generation are
> colored "young_card".  And there are a variety of reasons why cards colored
> "dirty_card" may remain so (see G1RemSet::refine_card()), so changing the
> assertion to test for no such cards doesn't work either.
> 
> Removed the G1RSLogCheckCardTable develop option that controlled the bogus
> assertion, since that's all that option does.
> 
> Removed CountNonCleanMemRegionClosure class, since it is no longer used.

Quick grepping showed that also CardTableModRefBS::mod_card_iterate() is
not used any more. Imo it should be removed too.

Thanks,
  Thomas