[cache] fix a cache issue with an entity created without relation cache prefill
Prefilling the relation cache has its benefits sometimes, but for
massive imports it may be a memory hog.
The caches should be kept coherent even if there was no prefill.
Closes #3828155.
/*
* cubicweb js mock for unit tests
* This module defines variables and functions used in quite a few places
* in cw js framework that can't be used or guessed without a real CW server
*/
var pageid = 'my-page-id';
function _(message) {
return message;
}