Test assets not available anymore for tests/functional/test_rx_gdbsim.py

[Pierrick Bouvier]

Hi all,

assets for tests/functional/test_rx_gdbsim.py are not available anymore.

It seems that the directory "https://acc.dl.osdn.jp/users"; vanished from 
the web, and it's not a temporary issue.
If someone still has those assets on their local cache, maybe it's a 
good time to upload them somewhere else, and update the test.

Thanks,
Pierrick