[SPARK-3967] don’t redundantly overwrite executor JAR deps

Hey @ryan-williams my concern is that if this fails (e.g. because of some permissions thing), then we will always have an old version of the file because `destFile.exists` will always be true down there in L440. It might make sense to throw an exception if delete is unsuccessful instead of logging an incorrect message here (I realize you just moved this code, but it would still be good to fix this).