Add a test to check validity of the yaml files

[hmaarrfk]

I'm not sure why, but it seems that the jasper2 migrator had some bugs in the yaml file that caused issues after it was merged during a rerender.

I think a simple test, that tries to "read" the yaml file, to ensure there are any bugs in the yaml syntax would go a long way.

I've addressed the immediate issue in ;
#1940

[akrherz]

I am so sorry for breaking things with jasper2.yaml. I just now reproduced what I did wrong

• View the previous PR diff here
• copy text shown and paste into vim jasper2.yaml file
• saved the file and found the non-ascii characters included

[hmaarrfk]

It seemed that I missed some other non-ascii characters
#1943