A short answer is no, the test platform is not included in the blink branch.
FWIW (to make it clear, I'm not the decision maker so just some of my own opinions), the test platform is for production usage and includes simulation of online jobs and probably some confidential stuff, so I don't think it could be rawly put out. However, there're indeed ongoing plan to extract test cases, benchmarks, etc. from the platform and contribute to Flink community, to enrich the Flink test suite. Please watch the news and discussions in flink mailing list for the progress (smile).