In 69a4d6ae, an MTR test was added to verify that we handled multiple invalid
options.  However, the logic to perform this test relied on a non-trivial regex
to filter out the noise in the logs.

Instead, we now just simply search for what we expect to be in the logs.

All new code of the whole pull request, including one or several files that are
either new files or modified ones, are contributed under the BSD-new license. I
am contributing on behalf of my employer Amazon Web Services, Inc.