Resolve “Successfully created” chatter and “illegal reflective access” errors from launch4j

[processing-bot]

Created by: benfry

When exporting an application for Windows, launch4j puts the following out to stderr, so we get red text in the console:

Compiling resources
Linking
Successfully created /path/to/sketch_200925b/application.windows64/sketch_200925b.exe

Would be good to shut this off, but we can't just ignore stderr since it may contain actual debug information.

Further, other warnings are generated during the process:

WARNING: An illegal reflective access operation has occurred
WARNING: Illegal reflective access by com.thoughtworks.xstream.core.util.Fields (file:/path/to/Processing.app/Contents/Java/modes/java/application/launch4j/lib/xstream.jar) to field java.util.Properties.defaults
WARNING: Please consider reporting this to the maintainers of com.thoughtworks.xstream.core.util.Fields
WARNING: Use --illegal-access=warn to enable warnings of further illegal reflective access operations
WARNING: All illegal access operations will be denied in a future release

which seems a little more important to actually resolve, though users won't see this unless they're looking at the system console.