Using a git submodule for the specifications tests doesn't work well with an Evergreen workflow; since Evergreen doesn't do a deep clone of the repository and applies the patch before our scripts, any changes to the tests in the patch will get overwritten by the submodule update. We should remove the submodule and replace it with a script/makefile target to update the tests.

Once we replace the generated spec tests with "parse and run" tests, we should remove all of the yaml spec files from the repo since we plan on only using the JSON ones.