Currently, when a tassert() is tripped, there is nothing in the command response to indicate that the failure was due to a tassert. In order to change the jstestfuzzer to fail when a command trips a tassert(), we must provide this.

There are a few possible ways of doing this, and we should discuss with service arch which is best:
-Prefix the error message with "tassert failed" or similar
-Add a new response field indicating that the failure was due to tassert().
-It may be possible to use 'extraErrorInfo' to include this information.