A number of our integration tests set up sample projects that contain
`package.json` files. These files aren't actually needed to run the
tests, so this commit removes them to clean up the repository a bit.
Co-authored-by: Will Jones <will@sacharissa.co.uk>
It appears that a large number of tests were using references
to main fields which don't currently exist. The runtime didn't
produce an error because package.json was being ignored.