Temporary workaround for long failure messages when running from AS

AS installs tests in such a way that they don't get necessary
permissions; the result is a long message starting with "Failed to get
system health diags" when a test fails.

While I'm looking for a good solution, removing this annoyance.

Change-Id: I9e439c3aefb9dd365c841c98d530b9346d7ccd10