Remove -j 1 from DWDS tests

[grouma]

#343 updated the dependencies so that we support build_daemon ^0.6.0. This version fixes race conditions and therefore we should be able to remove -j 1. Unfortunately, calling await webdriver.quit() within the teardown returns prior to webdriver actually finishes all calls. This results in a teardown failure. Probably should open an issue on package:webdriver and just add an artificial await.