WIP: Upgrade graphql-js Testdata Process

[dackroyd]

The process for pulling in test cases from graphql-js has been broken for a long time. The project has made an array of changes which prevent the existing approach from being functional, including migration to Typescript, changes to assertion helper functions and more.

With this change, the approach for integration is shifted. Rather than needing to clone the graphql-js repo, instead we pull it in as a dependency of the Node.js project under testdata. This is patched via patch-package in a postinstall hook, which causes the test functions to write the cases out, and those are collected and written to JSON.

As expected, the test cases have a significant number of updates, and the Go tests driven by them fail in their current state, so further work is required.