GitLab

regress: Add Fundamental type with no set/get-value-func's

A fundamental type may or may not provide set and get value functions,
the regress implementations always provide one, so define a new type
with no such functions so that we can test this case in Gjs.

To avoid repeating lots of duplicated code, we re-use the same
functions of RegressTestFundamentalObject when possible, by using the
same structure.