This splits the previous `op_url_parse` into:
- `op_url_parse`: parses a href with an optional base
- `op_url_reparse`: reparses a href with a modifier
This is a cleaner separation of concerns and it allows us to optimize & simplify args passed. Resulting in a 25% reduction in call overhead (~5000ns/call => ~3700ns/call in url_ops bench on my M1 Air)