Add compilation testing binary

[michaelmior]

This can be based off contrib/validate.cc, but we don't actually need to validate a document. Just verify that a schema is compiled correctly. Ideally, this would be a basis for future fuzz testing. This means that the program should not crash under any of the following conditions:

• Invalid JSON
• Unknown dialect
• Invalid schema (i.e., the schema doesn't validate according to the metaschema)

Really, the only case where it should crash if there's an unanticipated error during the compilation process. Exiting with non-zero status and an error message is fine.