Use page other than `chrome://terms` for bf-cache gatherer

https://github.com/GoogleChrome/lighthouse/blob/1d2a380d3c15e5848381fc1dd625837c5dc28ff6/core/gather/gatherers/bf-cache-failures.js#L107-L109

Marking for 11.0 not because it is a breaking change, but to keep on our radar to check on "sometime in the future".

Start with core/gather/gatherers/bf-cache-failures.js at lines 107-109 and inspect how the bf-cache gatherer uses chrome://terms. Determine which alternative page should be used, then verify that the gatherer still completes its bf-cache collection without relying on chrome://terms.

Written by the indexing model from the issue text.