JR 0.9 ignores #records_for, crashes from nonstandard #records

We've moved our main app to JR 0.9 (yay caching!) but are facing an issue where #records_for isn't being called to get associated records for a request with include param. Instead, the associated resource's #records method is being called.

I'm inclined to call this a regression, honestly, since #records_for is still documented as a potential hookup location for authorization code. I was actually just about to override this so that certain associations would ignore our authorization code, and found that it wasn't being called at all.

It doesn't appear to be a security issue for us (due to the way our authorization works), but this behavior could potentially cause security issues in other apps, depending on how they are architected (namely, if their #records_for authorized differently from their #records)

Strongly related: if the #records call on the associated resource causes some of the associations to be nonexistent, it causes an exception, since it can't find the ID of the associated record in the Hash it's built up for preload data

No files or tests are named. Start by tracing the include/preload path that calls the associated resource's #records, then compare it with the documented #records_for hook and the handling of missing association IDs. Done means the intended hook is used and nonexistent associated records no longer cause the preload lookup exception.