Helpers referenced from template before they are registered cause error #2
Description
Late-binding of path expressions need to support resolving helpers that were registered after the template was compiled. If the helper was registered beforehand, eager binding is still good for performance, but if we can't resolve the symbol at compile time, we should allow for the possibility that the symbol will eventually be a helper reference bound at runtime, and not assume it is a variable name reference.
Currently, because we don't allow for this possibility, references to helpers that haven't been registered yet and have inline arguments cause a compilation error, because the compiler does not collapse the arguments into a helper expression.