Unable to parse `SELECT 0 IS NULL`

[auntyellow]

Describe the bug
Unable to parse SELECT 0 IS NULL

To Reproduce
Steps to reproduce the behavior:

1. SELECT 0 IS NULL or SELECT 1 IS NOT NULL or SELECT 2 IN (0, 1)
2. Parsing this SQL using JSqlParser with this statements
3. Exception: net.sf.jsqlparser.parser.ParseException: Encountered unexpected token: "IS" at line 1, column 9. Was expecting one of: ...

Expected behavior
Should be able to parse statement.

System

• Database: MySQL (returns 0) and PostgreSQL (returns false)
• Java Version: 8
• JSqlParser version: 3.1, 3.2-SNAPSHOT (with latest master)

[auntyellow]

Looks duplicate with #720

[wumpz]

JsqlParser 4 parses this