Optionally dump the compiled tokenizer.

The compiled tokenizer is written to disk and then loaded with
`require` if the PARSOID_DUMP_TOKENIZER environment variable is set.

This is useful when debugging.  It is also useful for integration tests,
so that the code linting tools can be run on the tokenizer.

Change-Id: If8e4eaf42b34eaff93d906ab3caa30ce137f6555