Use systemctl to properly detect ephemeral ports on Mac OS (aka darwin) by fetching
systemctl values:
* net.inet.ip.portrange.first
* net.inet.ip.portrange.last
This will avoid the message:
`[INFO] freeport: ephemeral port range detection not configured for GOOS="darwin"`
and properly detect the correct port range
Currently when using the built-in CA provider for Connect, root certificates are valid for 10 years, however secondary DCs get intermediates that are valid for only 1 year. There is no mechanism currently short of rotating the root in the primary that will cause the secondary DCs to renew their intermediates.
This PR adds a check that renews the cert if it is half way through its validity period.
In order to be able to test these changes, a new configuration option was added: IntermediateCertTTL which is set extremely low in the tests.
This should cut down on test flakiness.
Problems handled:
- If you had enough parallel test cases running, the former circular
approach to handling the port block could hand out the same port to
multiple cases before they each had a chance to bind them, leading to
one of the two tests to fail.
- The freeport library would allocate out of the ephemeral port range.
This has been corrected for Linux (which should cover CI).
- The library now waits until a formerly-in-use port is verified to be
free before putting it back into circulation.