add core state lock deadlock detection config option

[troyready]

This was previously available via a build flag but will now be available as a configuration option.

This is an alternate approach to #17020 -- the UX and behavior is identical, but achieved in potentially a more straightforward way. Downside is relying on some global state.

[ncabatoff]

This looks good, except one concern I have. Doesn't the default config for Opts.OnPotentialDeadlock do an os.Exit(2)? We probably don't want that, right?