DDC-3765: [GH-1419] [DDC-3382] Allow orphan removal to be cancelled

[doctrinebot]

Jira issue originally created by user @doctrinebot:

This issue is created automatically through a Github pull request on behalf of c960657:

Url: #1419

Message:

I have a one-to-many relation with orphanRemoval=true.
If I remove an entity from the related collection and add it back, the entity is removed from the database.

$employee = $company->getEmployees()->first();
$company->getEmployees()->removeElement($employee);
$company->getEmployees()->add($employee);

$em->persist($company);
$em->flush();
// Now $employee is deleted from the database.

The expected behaviour is to leave the entity in the database, because it was present in the PersistentCollection when $em->persist() was called.

This has previously been suggested in [DDC-3382](http://www.doctrine-project.org/jira/browse/[DDC-3382]%28http://www.doctrine-project.org/jira/browse/DDC-3382%29), but it was rejected. This PR shows how small a change it is, so I hope the suggestion will be reconsidered in the light of this.

[doctrinebot]

• duplicates DDC-3382: [GH-1419] With orphanRemoval, cannot delete and re-add entity

[doctrinebot]

Comment created by @doctrinebot:

A related Github Pull-Request [GH-1419] was merged:
#1419