BATCH-2144 Exclude long running test (same behavior as Maven)

* `$ mvn clean install -P bootstrap,all` does not run all tests. Exclude those additional tests from the Gradle build by default. They can be activated by providing the the `alltests` parameter, e.g.: `./gradlew clean build -Palltests`
* Execute the exact same tests as the Maven build
* Improve execution speed of Gradle build