See nexedi/erp5@8fdc1a15

Add tests to prevent future regression.

This is not a regression, only the test getting better at spotting an
incorrect behaviour which pre-existed.

Also, while exporting catalog methods, explicitly check for `expression_instance` property.
Now we keep expression_instance property in a volatile attribute, so we should prefer using
it.

When data-gadget-renderjs-extra attribute is not set to an element,
`element.getAttribute("data-gadget-renderjs-extra")` returns null.

Possible error messages :
- sub_key is null
- TypeError: Cannot set property 'key' of null

/reviewed-on nexedi/erp5!602

In case of catalog methods where we have expression empty or None, trying to get
expression_instance raises an error. So, as to keep the compatibilty with how it
used to check for value of expression as shown in this diff :
nexedi/erp5@04f331a2
its better to check the same in mixin.

This commit:

- Adds a new Activity called "SQLJoblib"
- Adds a Backend to be used by joblib
- Uses OOBTree to store results instead of ConflictFreeLog
- Adds a getResultDict API to fetch resut Dict

It uses the original work from rafael@nexedi.com and loic.esteve@inria.fr

to use new CKEditor test macros

Add Base_viewFieldLibrary/my_core_mode_required_text_content_validator

/reviewed-on !598

/reviewed-on !597

Also, as this error is returned via reponse code 403, we don't expect the element
to be present. Hence there is no need to keep that check anymore.

Use this dialog in test to check if it correctly raises implementation error
when trying to access this dialog.