Commit e739f2b779 ("cql3: expr: make evaluate() return a
cql3::raw_value rather than an expr::constant") introduced
raw_value::view() as a synonym to raw_value::to_view() to reduce
churn. To fix this duplication, we now remove raw_value::to_view().
raw_value::to_view() was picked for removal because is has fewer
call sites, reducing churn again.
Closes#10819