(#22363) Add alternative Visitor impl that may prove faster

This adds an alternative Visitor implementation that may prove
to be faster in certain situations. The current benchmarks are
however too simplistic to give a good indication. It seems to be
on par with the previous implementation for simple cases. It is
worth keeping this implementation for later use with larger benchmarks.
(#22363) Add validation of case and hash.

There were validation missing for case and case options (rvalue checks)
Checks were added for hash entries (they must be rvalues)

There were code to transform and dump the removed InstanceReferences
Pops model object. This commit removes that dead code.
(#22363) Add additional rvalue checks to if, unless, and literal list

This also includes some cleanup and spelling corrections.