Resource handling should check if classpath element is a jar

[galderz]

Non zip/jar dependencies still causing issues even after #3071, but in a different place:

[jbang] native-image: /opt/graalvm-ce-java11-21.1.0/bin/native-image -H:+ReportExceptionStackTraces --enable-https --class-path=/home/g/.m2/repository/org/graalvm/nativeimage/svm/21.1.0/svm-21.1.0.jar:/home/g/.m2/repository/org/graalvm/nativeimage/svm-hosted-native-linux-amd64/21.1.0/svm-hosted-native-linux-amd64-21.1.0.tar.gz:/home/g/.m2/repository/org/graalvm/nativeimage/svm-hosted-native-darwin-amd64/21.1.0/svm-hosted-native-darwin-amd64-21.1.0.tar.gz:/home/g/.m2/repository/org/graalvm/nativeimage/svm-hosted-native-windows-amd64/21.1.0/svm-hosted-native-windows-amd64-21.1.0.tar.gz:/home/g/.m2/repository/org/graalvm/sdk/graal-sdk/21.1.0/graal-sdk-21.1.0.jar:/home/g/.m2/repository/org/graalvm/nativeimage/objectfile/21.1.0/objectfile-21.1.0.jar:/home/g/.m2/repository/org/graalvm/nativeimage/pointsto/21.1.0/pointsto-21.1.0.jar:/home/g/.m2/repository/org/graalvm/compiler/compiler/21.1.0/compiler-21.1.0.jar:/home/g/.m2/repository/org/graalvm/truffle/truffle-api/21.1.0/truffle-api-21.1.0.jar -jar /home/g/.jbang/cache/jars/example.java.b7acb0fb141a742e1c2330740349f80d781b326cd18722d42830d9a0d0617df8.jar /home/g/.jbang/cache/jars/example.java.b7acb0fb141a742e1c2330740349f80d781b326cd18722d42830d9a0d0617df8.jar.bin
[jbang] log: /tmp/jbang9920023040190163357native-image
Error: Unable to handle classpath element '/home/g/.m2/repository/org/graalvm/nativeimage/svm-hosted-native-linux-amd64/21.1.0/svm-hosted-native-linux-amd64-21.1.0.tar.gz'. Make sure that all classpath entries are either directories or valid jar files.
com.oracle.svm.core.util.UserError$UserException: Unable to handle classpath element '/home/g/.m2/repository/org/graalvm/nativeimage/svm-hosted-native-linux-amd64/21.1.0/svm-hosted-native-linux-amd64-21.1.0.tar.gz'. Make sure that all classpath entries are either directories or valid jar files.
	at com.oracle.svm.core.util.UserError.abort(UserError.java:68)
	at com.oracle.svm.hosted.ResourcesFeature.duringAnalysis(ResourcesFeature.java:175)
	at com.oracle.svm.hosted.NativeImageGenerator.lambda$runPointsToAnalysis$14(NativeImageGenerator.java:765)
	at com.oracle.svm.hosted.FeatureHandler.forEachFeature(FeatureHandler.java:71)
	at com.oracle.svm.hosted.NativeImageGenerator.runPointsToAnalysis(NativeImageGenerator.java:765)
	at com.oracle.svm.hosted.NativeImageGenerator.doRun(NativeImageGenerator.java:582)
	at com.oracle.svm.hosted.NativeImageGenerator.lambda$run$2(NativeImageGenerator.java:495)
	at java.base/java.util.concurrent.ForkJoinTask$AdaptedRunnableAction.exec(ForkJoinTask.java:1407)
	at java.base/java.util.concurrent.ForkJoinTask.doExec(ForkJoinTask.java:290)
	at java.base/java.util.concurrent.ForkJoinPool$WorkQueue.topLevelExec(ForkJoinPool.java:1020)
	at java.base/java.util.concurrent.ForkJoinPool.scan(ForkJoinPool.java:1656)
	at java.base/java.util.concurrent.ForkJoinPool.runWorker(ForkJoinPool.java:1594)
	at java.base/java.util.concurrent.ForkJoinWorkerThread.run(ForkJoinWorkerThread.java:183)

The fix would be simple (add a check to see if the element is a jar before calling scanJar). However, testing this is a little more tricky since I'm unsure how to generate an svm pom.xml that has tar.gz dependencies (see slack question).