fix environent tests for heap size calculation change in v8 5.1
fix environent tests for heap size calculation change in v8 5.1

kgriesh/appmetrics,seabaylea/appmetrics,RuntimeTools/appmetrics,hhellyer/appmetrics,hhellyeribm/appmetrics,mattcolegate/appmetrics,seabaylea/appmetrics,RuntimeTools/appmetrics,stalleyj/appmetrics,sjanuary/appmetrics,hhellyeribm/appmetrics,hhellyer/appmetrics,kgriesh/appmetrics,stalleyj/appmetrics,RuntimeTools/appmetrics,seabaylea/appmetrics,RuntimeTools/appmetrics,sjanuary/appmetrics,mattcolegate/appmetrics,hhellyeribm/appmetrics,hhellyer/appmetrics,hhellyeribm/appmetrics,mattcolegate/appmetrics,kgriesh/appmetrics,stalleyj/appmetrics,stalleyj/appmetrics,RuntimeTools/appmetrics,stalleyj/appmetrics,sjanuary/appmetrics,hhellyeribm/appmetrics,sjanuary/appmetrics,hhellyer/appmetrics,hhellyer/appmetrics,mattcolegate/appmetrics,kgriesh/appmetrics,mattcolegate/appmetrics,seabaylea/appmetrics,seabaylea/appmetrics