This PR adds a test for mysql2 auto instrumentation for @sentry/node-experimental.

mysql2 will not query unless there is a connection and it does not want to work without one like mysql.

This PR adds a withDockerCompose method to the test runner which handles:

• Starting the docker container
• Waiting until some specific output has been seen from the container so we know the server is up
• Closing and cleaning up the docker container/volumes

 createRunner(__dirname, 'scenario.js')
      .withDockerCompose({ workingDirectory: [__dirname], readyMatches: ['port: 3306'] })
      .expect({ transaction: EXPECTED_TRANSACTION })
      .start(done);

My only minor concern is that the mysql docker container creates a volume to store data. If the cleanup code does not run, a 180MB volume is left behind after every run. This will only be an issue when testing locally but we could start to fill developers machines. These can be cleaned up via docker volume prune --force but I would not want to run this on peoples machines without telling them!