Request for review (XS): 7030435: Some oop_oop_iterate_m() methods iterate outside of specified memory bounds

[Y. Srinivas Ramakrishna]

This fixes the issues found by the newly added
assert in the card-table verification closure, apropos
of my last code review request.

Tested in the same manner as described in the code
review request for 7029036 that i sent a little while
ago.

webrev: http://cr.openjdk.java.net/~ysr/7030435/webrev.00/

Many thanks for your reviews!
-- ramki