This fixes processing of WeakMaps so that value entries on an evacuation
candidate are correctly recorded in the slots buffer. We didn't pass the
correct slot into the backing hashtable while visiting values.

Also the live bytes counter for large object space pages was not reset
correctly when incremental marking is aborted.

R=vegorov@chromium.org
BUG=v8:2060
TEST=cctest/test-weakmaps/Regress2060

Review URL: https://chromiumcodereview.appspot.com/10034010

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@11264 ce2b1a6d-e550-0410-aec6-3dcde31c8c00