run.py: add options for starting JVM with a debugger server

To start the JVM with debugger server just run:

  sudo scripts/run.py -nv --jvm-debug

If you want the JVM to wait for debugger client:

  sudo scripts/run.py -nv --jvm-suspend

Listens on port 5005.

Signed-off-by: Tomasz Grabiec <tgrabiec@cloudius-systems.com>
Signed-off-by: Pekka Enberg <penberg@cloudius-systems.com>
run.py: do not modify input parameter in set_imgargs()

Functions which do not modify input parameters are easier to analyze
and more friendly for its users.

Signed-off-by: Tomasz Grabiec <tgrabiec@cloudius-systems.com>
Signed-off-by: Pekka Enberg <penberg@cloudius-systems.com>