[SQL] [MINOR] use catalyst type converter in ScalaUdf

It's a follow-up of https://github.com/apache/spark/pull/5154, we can speed up scala udf evaluation by create type converter in advance.

Author: Wenchen Fan <cloud0fan@outlook.com>

Closes #6182 from cloud-fan/tmp and squashes the following commits:

241cfe9 [Wenchen Fan] use converter in ScalaUdf