Debug Tags of Plugins Cannot Be Turned On at Startup

I tried to turn on a debug tag for a plugin, but didn't see the debug prints. I tried using the `traffic_server -T ` command line option, and editing `records.yaml` and setting `ts.diags.debug.tags`. Neither caused debug messages to print.

I think the problem is that the tags are evaluated before plugin load, and somehow the code to check if new debug tags are turned on via the regex is somehow not giving the correct value for the plugin's tag.

I'm working around this currently by adding code to `DbgCtl::_new_reference` to hard-code tags to turn on by name.