Deduplicate test case files and test syntax in language module

[reid-spencer]

The test cases have been hacked together for 4 years. They need to get a bit more organized and de-duplicated. For example, rbbq.riddl appears in three places with the same content. Same for everything.riddl. These should be deduplicated from the various src/test/input folders.

In the language module. Use of such test files should be constrained to narrow aspects of the language. MOre comprehensive tests should end up in testkit