Change total memory check

1. fix the reported failure with mem_total_list values
2. add variance check in case of different total memory report

BUG=chromium:33965
TEST=test locally

Change-Id: I3defbb72e91382a694b31ef5ce048047ee990f46
Reviewed-on: https://chromium-review.googlesource.com/232813
Reviewed-by: Kalin Stoyanov <kalin@chromium.org>
Commit-Queue: Helen Zhang <helenzhang@chromium.org>
Tested-by: Helen Zhang <helenzhang@chromium.org>
1 file changed