Remove background command line window

[tobiasdiez]

Currently, a console window is shown in the background. Reason is the command-line argument to jpackage which enables command line input. Thus, currently we have to life with the background console window.

Java bug report: https://bugs.openjdk.java.net/browse/JDK-8234469

[koppor]

Current (visible) state: The JDK guys ask for feedback:

I cannot reproduce with simple example, and have emailed submitter for further instructions.

https://bugs.openjdk.java.net/browse/JDK-8234469?focusedCommentId=14301796&page=com.atlassian.jira.plugin.system.issuetabpanels%3Acomment-tabpanel#comment-14301796

[koppor]

The upstream bug was closed. We have to write a MWE, don't we? @tobiasdiez

[koppor]

Is https://github.com/tobiasdiez/javatestbed the MWE? (item 2 in README.md?)