Errors occurring when generating unrolled test names should cause test failures

[erdi]

I find myself often breaking generation of unrolled test names when refactoring my tests, e.g. renaming variables in where blocks. I only tend to learn about it when my tests fail and I look at test names which contain Error:... in reports. I find it very annoying that I have to then fix the test name generation to understand the failure better, especially if the failure occurred on the CI.

I think that instead of placing #Error:offenidingVariableName in test name in such case Spock should fail the test to attract my attention to the problem with test name generation. I'm happy for this to be configurable with current behaviour staying the default to preserve backwards compatibility and avoid a breaking change.