Application `[No Application] - Headless Mode` unsupported. - Should be default

[jgsuess]

In the Junit Runner application, there is a setting to run the built-in Eclipse JUnit runner. It hides behind a drop-down setting of [No Application] - Headless Mode. It would be nice to include this setting or even make this the default. I am unsure how else I can use the DSL without this at the moment - the validation fails as the editor does not know about this.

The default application name is org.eclipse.pde.junit.runtime.application for headless, and something with UI for running with widgets. It would be great if you could add this, as headless tests are very common.