Implement step 4 of the Overload retry policy and the propose tests modifications done to source/retryable-reads/tests/README.md in https://github.com/mongodb/specifications/commit/1b15cd299011172f941893cbe3c9d4737cb2ee5d.

Note that the "If the request is eligible for retry" part of the specification is completely irrelevant: one may add the previously used server's address to the list of deprioritized server addresses for server selection regardless of the eligibility for retry, and if there is no another retry attempt, then the list will simply be ignored as there will be no another server selection.

Addressing the source code notes tagged with TODO-JAVA-6167 is in scope of this ticket.