LP:711801 - Sporadic wrong result with mrr_sort_keys

The following RQG command line reports

perl runall.pl -queries=1M --duration=300 --threads=2 --seed=time --reporter=QueryTimeout,Deadlock,Backtrace,ErrorLog --validator=Transformer --filter=conf/optimizer/dsmrr-cpk.ff --no-mask --mysqld=sql_mode=ONLY_FULL_GROUP_BY --mysqld=optimizer_search_depth=6 --debug --notnull --engine=InnoDB --mysqld=-join_cache_level=7 --grammar=conf/optimizer/optimizer_no_subquery.yy --queries=100000000 --mask=35033 --basedir=/home/philips/bzr/maria-5.3-mwl128 --seed=1296569756 --threads=1 --duration=900

reports a single query that returns different results with different execution plans. Issue is not repeatable with an MTR test case. Issue goes away with mrr_sort_keys=off,index_condition_pushdown=off .