Make the new renaming infrastructure compatible with Xbase languages.

[gallandarakhneorg]

According to the change log of Xtext 2.13, a new renaming infrastructure is provided, based on IChangeSerializer.

According to the documentation of RefactorElementNameFragment2, this new infrastructure cannot be used for Xbase-based languages.

According this dicussion, the core problem is related to the derived state, which is ignored by the new infrastructure.

Assuming Xbase-based languages cover a large portion of the languages written with Xtext, it may be valuable to extend the usage of IChangeSerializer to Xbase-based languages too.