Expand tests for 802.1x wired networks

The first version of this test only verified successful
authentication when a) the credentials were available, then
b) an EAP authenticator was detected.  The test only
validated by checking the device's authentication state, and
required a relatively long "sleep".  This change:

  - Fixes the sleep by using shill_proxy's internal
    "wait_for_property_in" functionality.
  - Checks hostapd's state to make sure the client is actually
    authenticated.
  - Temporarily removes EAP credentials and makes sure hostapd
    receives an EAPOL logout event, then re-authenticates.
  - While here, move IP and MAC address querying out to a new
    separate module that can be shared.

CQ-DEPEND=CL:48803
BUG=chromium:234290
TEST=This is a test.  Also run network_DhcpNegotiationSuccess for
regression testing of IP address query functions.

Change-Id: I76dd4f0753986914824e0cdcbcf3583d08a4f7cb
Reviewed-on: https://gerrit.chromium.org/gerrit/48806
Commit-Queue: Paul Stewart <pstew@chromium.org>
Reviewed-by: Paul Stewart <pstew@chromium.org>
Tested-by: Paul Stewart <pstew@chromium.org>
5 files changed