Example issue with build tool dependencies for swift-java

This repository highlights a bug found with the Swift Package Manager's dependency handling for build tool plugins. The package doesn't build because the Java2SwiftPlugin isn't seeing the "JavaKit" dependency of the "JavaMath" target. If we uncomment the marked line in Package.swift to also add a "JavaKitJar" dependency, we see both the JavaKit and JavaKitJar dependencies correctly.