autotest (wifi): dynamically probe for IBSS capability

Some hardware does not support IBSS mode. Accordingly, we should
check hardware capabilities before reporting CAPABILITY_IBSS.

The exact division of labor between LinuxRouter and LinuxSystem
is not obvious to me. I'm moving IBSS detection into LinuxSystem,
because it's quite reasonable to use IBSS on a system that's not
a router.

Note: tests do not currently verify that a DUT supports IBSS.
If we add DUTs that do not support IBSS, we'll need to update
the relevant test(s).

While there: fix typo in iw_runner.

BUG=chromium:504926
TEST=test_that chromeos1-dev-host6.cros network_WiFi_IBSS.wifi_IBSS
TEST=test_that chromeos1-row3-rack11-host1.cros network_WiFi_IBSS.wifi_IBSS

First command should report PASSED, but with TEST_NA. Second command
should just report PASSED.

Change-Id: I8e875b7a137f2451493194bd12d95e435f68d61f
Reviewed-on: https://chromium-review.googlesource.com/282162
Reviewed-by: Paul Stewart <pstew@chromium.org>
Tested-by: mukesh agrawal <quiche@chromium.org>
Commit-Queue: mukesh agrawal <quiche@chromium.org>
Trybot-Ready: mukesh agrawal <quiche@chromium.org>
3 files changed