Enable 'Never join already wrapped lines' option of the Java formatter

From #741 (comment 1799658):

Keep breaking of lines in formatter for now, but investigate 'Never join already wrapped lines' option.

There was a long discussion about this in #741 (closed). The concrete action is to see if we can prevent lines being 'rejoined' by not using an option in the formatter that seems to have that goal. This needs to be tried out, and see how it works, what the consequences are, and whether it brings what we aim for.

Addresses #741 (closed)