Passing --debugger with no port can cause other arguments to be ignored

[ctrueden]

For example:

ImageJ --debugger --update list-modified

Results in a random port being chosen for remote debugging, but then the main ImageJ application window appears rather than executing the intended command-line Updater action.

Whereas this invocation works as desired:

ImageJ --debugger= --update list-modified

Relatedly:

ImageJ --debugger=suspend --update list-modified

Does not respect the suspend, but does execute the updater action.

Noticed by @joshmoore.