0) Add the jtokkit test suite examples to validate the cl100k_base, p50k_base & r50k_base encodings

[paplorinc]

See:

• https://github.com/knuddelsgmbh/jtokkit/blob/main/lib/src/test/resources/cl100k_base_encodings.csv
• https://github.com/knuddelsgmbh/jtokkit/blob/main/lib/src/test/resources/p50k_base_encodings.csv
• https://github.com/knuddelsgmbh/jtokkit/blob/main/lib/src/test/resources/r50k_base_encodings.csv

To make it simpler and smarter to input the parameters, instead of the CSV inputs I've pushed them as code.

I've split out the tests from the optimization work I've started here, see:

• https://github.com/openai/tiktoken/pull/234