testERP5Catalog: test new related key syntaxes

In 4bcf5c6a (CatalogTool: Introduce new dynamic related key syntax, 2017-07-25)
we introduced a new syntax to solve some ambiguities in the previous syntax, but
the test suite was still testing the old syntax only.

Update tests to test the new syntax and to also check the old legacy syntax.
8 jobs for fix/related_keys_test in 0 seconds (queued for 4 seconds)
Status Job ID Name Coverage
  External
passed ERP5.CodingStyleTest-TestRunner2

failed ERP5.UnitTest-TestRunner2

01:15:34

failed ERP5.CodingStyleTest-TestRunner2

00:48:52

canceled ERP5.CodingStyleTest-TestRunner2

00:00:02

failed ERP5.UnitTest-TestRunner2

03:50:37

canceled ERP5.UnitTest-TestRunner2

failed ERP5.UnitTest-TestRunner2

01:23:42

canceled ERP5.UnitTest-TestRunner2