findVersions across a historyless and a historied object finds nothing

[tobias-]

If you do findVersions() on a history object that references a non-versioned and then a versioned object again, a systime <@ null will be added to the query (postgres) which will of course always fail.

ie.

QHistoriedA(db)
  .where()
  .historyLessB.historiedC.deleted.isNotNull
  .findVersions()

This will erronously add a systime constraint which never matches (systime <@ null) in postgres. H2 adds a syntactically different, but it has the same problem. Other databases are untested but assumed to fail the same way.

Expected behavior

Return list of matching results

Actual behavior

Always returns zero records

Steps to reproduce

#3082 has a testcase showing it