ptrace_allow_access doesn't check supplementary groups when checking access.

Issue

• There are cases when doing parallel debugging that primary group access is not quite enough to debug code.
• When it is just a local problem it is easy to just run newgrp and then rerun the debugger but there is no provision for having the debugger stub to change its credentials and restarting itself with a new primary credential.
• Thus it is believed that the logic in __ptrace_allow_attach is insufficient. It should also check the supplementary group.