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

This reverts commit 3840b34da05248d91bf3d2a7f1c30f7fa0d63891.

Reason for revert: No longer needed, as the ART Buildbot no longer
uses devices running Android Oreo.

Test: art/tools/run-libcore-tests.sh --mode=device
Bug: 74725685
Change-Id: Ifc99137920a6799aa53db0fced27ffda4dc284da
2 files changed