autotest: correct dark resume count check in active scans test

Correct the check to verify the number of dark resume that occured during
network_WiFi_DarkResuemActiveScans to properly account for the fact that the
dark resume count is cumulative for the main body of the test.

BUG=None
TEST=Run network_WiFi_DarkResuemActiveScans on samus servo wificell.

Change-Id: I00af4b1c9835cd1d5e01939660383d23d201b91a
Reviewed-on: https://chromium-review.googlesource.com/263957
Tested-by: Samuel Tan <samueltan@chromium.org>
Reviewed-by: Eric Caruso <ejcaruso@chromium.org>
Commit-Queue: Samuel Tan <samueltan@chromium.org>
1 file changed