lib/libc/tests/rpc: Start rpcbind(8) if needed

[arichardson]

Summary

This uses the same approach as the auditd(8) tests and starts a rpcbind
service on-demand. This allows changing the SKIPX calls to ERRX as we can
now expect all the tests to pass.

[ngie]

I don't think this is a good idea. Tests really shouldn't be starting services because it can make the tests more flaky, it can mutate system state, and might interfere with other service management systems, like Isilon has on OneFS.

[arichardson]

In D28479#637433, @ngie wrote:

I don't think this is a good idea. Tests really shouldn't be starting services because it can make the tests more flaky, it can mutate system state, and might interfere with other service management systems, like Isilon has on OneFS.

There are a few other tests that do this, but I agree that it is a bit fragile. The other tests that start services should probably also be adjusted.

Alternatively the service startup could be restricted to CI setup?
I.e. guarding the service startup with:

if (atf_tc_get_config_var_as_bool_wd(tc, "ci", false))

[arichardson]

Not a good idea, will drop.