Regression with immutable POJO, `@JsonIdentityInfo`, for 3.0

[cowtowncoder]

Fix for #5238 (see #5239) exposes a problem with POJO case, for 3.0 -- see JsonIdentityOnRecord5238Test.java for failure:

[ERROR]   JsonIdentityOnRecord5238Test.testIdentityWithPojo:58 » Databind Invalid Object Id definition for `tools.jackson.databind.records.JsonIdentityOnRecord5238Test$ThingPojo`: cannot find property with name 'id'
 at [No location information] (through reference chain: tools.jackson.databind.records.JsonIdentityOnRecord5238Test$ExamplePojo["allThings"]->java.util.ImmutableCollections$List12[0])
[INFO] 

Hopefully can be resolved; or if not immediately, need to move under tofix tests.