Update Presto functions coverage map (facebookincubator#9309)

Summary:
Updated the complete list of Presto scalar functions using output from `SHOW FUNCTIONS` command.

Re-generated coverage maps using instructions from
`velox/functions/prestosql/coverage/README.md`.

Pull Request resolved: facebookincubator#9309

Reviewed By: xiaoxmeng

Differential Revision: D55641760

Pulled By: mbasmanova

fbshipit-source-id: e2dbaa23135682c060c8a2900cf4c967191a6f46