simplify 'handles corrupt JSON files' test
simplify 'handles corrupt JSON files' test

The 'handles corrupt JSON files' test doesn't need to spawn a subprocess, it
just has to inject the corrupt JSON file into the output directory.

istanbuljs/nyc,Lalem001/nyc,novemberborn/nyc,lloydcotten/nyc,schutm/nyc,isaacs/nyc,bcoe/nyc