Minor relcond resolver refactor, no func. changes
Simplify self_result_object argument check in cond resolver
No longer use rel_info($rel)->{class} in the cond resolver

It turns out there are a lot of codebases there containing garbage in the
rel definition. Punt for after 0.082800 to lean up that mess.

Also be less strict on checking the foreign_values contents - downgrade
mismatches to a warning (but still hard-require ::Row ancestry)