JFR: Preserve disk repository after exit

Today the repository where .jfr chunk files are stored is deleted when the JVM exists.This is in most cases a desirable behavior as it prevents the disk from filling up by default.

That said, I think we should consider adding an option to allow it to not be removed. If the JVM exists, for example on an OOM, and is not able to dump an emergency recording, it might make sense to keep it. It would then be the users responsibility to clean it up. This is the same behaviour as for ordinary log files.

Another use case is to archive everything that happened during a longer run. A dump file at the end might be to large (several gigabytes) to be practical to open in JMC, downloading from a web server or storing in an object storage.

A parameter could be passed to -XX:FlightRecorderOptions