stats: Remove --use-fake-symbol-tables option.

[jmarantz]

See also #6307 which removes the code supporting fake symbol tables, but leaves the option in place.

Removing the option is a breaking change, so splitting that off on its own.

[mk46]

Hi @jmarantz, I would like to take it if you're not working on it.

[jmarantz]

You are welcome to take it; I expect it will be pretty easy and I can review. However, I think it would be better to wait a bit, because removing an option can break production setups, potentially. @mattklein123 when do you think would be appropriate? Maybe 1-2 weeks prior to the cut-date for 1.17?

[mattklein123]

If the code was removed in the last release IMO it can be removed any time during this cycle so fine to do it now.