wiki check: better failure message

Wiki Check jenkins run 11780 produced output
```
03:32:02 Running shadow replication tests on ibex_developers_manual
03:32:02
03:32:02 Running tests...
03:32:02 ----------------------------------------------------------------------
03:46:56 ..................................................................................................................................................................................................................................
[Pipeline] }
[Pipeline] // stage
[Pipeline] stage
[Pipeline] { (Declarative: Post Actions)
[Pipeline] junit
03:46:56 Recording test results
03:46:56 [Checks API] No suitable checks publisher found.
[Pipeline] }
[Pipeline] // stage
[Pipeline] }
[Pipeline] // timestamps
[Pipeline] }
[Pipeline] // timeout
[Pipeline] }
[Pipeline] // withEnv
[Pipeline] }
[Pipeline] // node
[Pipeline] End of Pipeline
ERROR: script returned exit code 1
Finished: FAILURE
```
comparing this to a successful run it would seem that possibly python crashed when running the tests, resulting in no XML being generated.

## Acceptance Criteria

* Better log message as to cause of python crash/issue