Only throw exceptions in one place

Drops the custom error message on `orderBy`. Note that by the logic of the recently merged code the same customization should also be applied to the walkers for the following nodes, not just orderBy:

````
OperandDynamicField
OperandDynamicFullTextSearchScore
OperandDynamicLength
OperandDynamicLocalName
OperandDynamicLowerCase
OperandDynamicLowerCase
OperandDynamicName
OperandDynamicUpperCase
OperandDynamicUpperCase
````

I could do this before tomorrow, but it wouldn't be wise for a stable release.