Make the PrettyFormatter work by revering to all-steps-first execution

Resolve the mismatch between the PrettyFormatter in the Gherkin library and Cucumber-JVM, by reverting to the all-steps-first-execution which was used in Cucumber-JVM version 1.1.2.
This is safe since the JSONFormatter issues triggering the change to one-step-at-the-time execution in Cucumber-JVM version 1.1.3 (https://github.com/cucumber/cucumber-jvm/pull/426) has been resolved by https://github.com/cucumber/gherkin/pull/216 in Gherkin 2.12.0. The JSONFormatterTest added in https://github.com/cucumber/cucumber-jvm/pull/426 verifies this.