io.quarkus.test.common.NativeImageLauncher.guessPath() needs to support > Java 9

[oztimpower]

The NativeImageLauncher.guessPath() is a method described as a hack to work in IDEs. The code uses URLClassLoader, which has changed to jdk.internal.loader.ClassLoaders$AppClassLoader if using Java11 for example.

(jdk.internal.loader.ClassLoaders$AppClassLoader cannot be cast to class java.net.URLClassLoader (jdk.internal.loader.ClassLoaders$AppClassLoader and java.net.URLClassLoader are in module java.base of loader 'bootstrap'))

Implementation ideas
I hacked guessPath() to look for my Maven "target" folder if it exists as the first check, a reasonable assumption, which did work, which can be done even before it enters the big class loader loop to cater for Gradle et al.

Please add support for the new class loader, plus the directories being checked do not seem to align with the current output folder default for NativeImage which is target/ for Maven.

[gsmet]

/cc @jaikiran @stuartwdouglas