We shouldn't log and login errors generated during unit tests.
<rdar://problem/111696020>
Pull request: https://github.com/WebKit/WebKit/pull/15507
Committed 276780@main (664d22e6961c): <https://commits.webkit.org/276780@main> Reviewed commits have been landed. Closing PR #15507 and removing active labels.
Committed 272448.897@safari-7618-branch (54d88072a5ec): <https://commits.webkit.org/272448.897@safari-7618-branch> Reviewed commits have been landed. Closing PR #1188 and removing active labels.