Make threads tests more stressful under AUTOMATED_TESTING
Make threads tests more stressful under AUTOMATED_TESTING

Increases number of inserts and number of threads in test to trigger race
condition reported in PERL-407

kainwinterheart/mongo-perl-driver,xdg/mongo-perl-driver,dagolden/mongo-perl-driver,gormanb/mongo-perl-driver,kainwinterheart/mongo-perl-driver,gormanb/mongo-perl-driver,mongodb/mongo-perl-driver,rahuldhodapkar/mongo-perl-driver,rahuldhodapkar/mongo-perl-driver,jorol/mongo-perl-driver,rahuldhodapkar/mongo-perl-driver,mongodb/mongo-perl-driver,dagolden/mongo-perl-driver,xdg/mongo-perl-driver,jorol/mongo-perl-driver,mongodb/mongo-perl-driver,dagolden/mongo-perl-driver,kainwinterheart/mongo-perl-driver,jorol/mongo-perl-driver,xdg/mongo-perl-driver,kainwinterheart/mongo-perl-driver,dagolden/mongo-perl-driver,gormanb/mongo-perl-driver,jorol/mongo-perl-driver,rahuldhodapkar/mongo-perl-driver,gormanb/mongo-perl-driver