Ignore failures on O devices in some network-related libcore tests.

These tests fail with the following assertion when run with an
unbundled ART (built from AOSP) on devices running Android O (MR1):

  android.system.ErrnoException: connect failed: EBADMSG (Not a data message)

This is a workaround to stop bot spam while we investigate the root of
the issue.

Test: art/tools/run-libcore-tests.sh --mode=device
Bug: 74725685
Change-Id: Ia7129eca795f4b1b01e50820f952bc5f36726d9a