This generates the evaluator factories which we'd been implementing
inline with `->`. The advantage of generating them is that they have a
useful `toString` and class name. These are useful for debugging and let
us remove a kind of errant use `ThrowingDriverContext` just to generate
a factory description for logging. Now we can just use the generated
`toString`.

…/compute/ann/Fixed.java

Co-authored-by: Alexander Spies <[email protected]>

…think' into esql_gen_tostring_think