autotest: Remove WiFi entries from the default profile in tests

Prevent WiFi entries from previous tests from interfering with future
tests by removing them from default profiles.  Other sources of WiFi
entries are already addressed by popping and removing other profiles.

TEST=Manually added a WiFi entry to the default profile in a DUT, then
ran network_WiFi_SimpleConnect.wifi_checkWPA_TKIP, which removed that
entry from the default profile.
BUG=chromium:332421

Change-Id: Ia3832fada48fefbaf682e643b99754eb577fb34f
Reviewed-on: https://chromium-review.googlesource.com/181891
Tested-by: Christopher Wiley <wiley@chromium.org>
Reviewed-by: Paul Stewart <pstew@chromium.org>
Commit-Queue: Christopher Wiley <wiley@chromium.org>
3 files changed