options_validate: add ClientUseIPv4 unit tests and update other unit tests
#17076 (moved) adds unit tests for options_validate. It's been merged to master.
#17840 (moved) adds ClientUseIPv4 and ClientPreferIPv6DirPort, and changes the meaning of other options. It was based off pre-#17076 master.
This ticket is for updating the unit tests after #17840 (moved) merges.