[JENKINS-28110] Reproduced problem in test.

Starting in 4f24a027 (1.587-SNAPSHOT, before #1443 or stapler #39), nestedDescribableOverridingId passes.
nestedDescribableSharingClass fails given {stapler-class: D3, kind: d3a}.
(Stapler has no way of interpreting kind since it knows nothing of Descriptor, only implementation class names.)
In master (3080573a), both fail in the way reported (only kind is passed in).
After adding stapler-class back, nestedDescribableOverridingId passes again.