Incorrect result from Parse.Query on Postgres

New Issue Checklist

• [ x] I am not disclosing a vulnerability.
• [ x] I am not just asking a question.
• [ x] I have searched through existing issues.
• [ x] I can reproduce the issue with the latest version of Parse Server.

Issue Description

When I try to request some data, I got results which supposed not to be there

Steps to reproduce

let query = new Parse.Query('Foo');
let subquery = new Parse.Query('Bar');
subquery.contains('name', FILTER);
query.matchesQuery('bar', subquery);

The query result also includes all Foo-objects whose 'bar' field is undefined or null, regardless of the value of FILTER.
I think this is wrong behavior.

Server

• Parse Server version: 4.4.0
• Operating system: Ubuntu 18.04
• Local or remote host (AWS, Azure, Google Cloud, Heroku, Digital Ocean, etc): Local

Database

• System (MongoDB or Postgres): Postgres
• Database version: 10.6
• Local or remote host (MongoDB Atlas, mLab, AWS, Azure, Google Cloud, etc): Local

Client

• SDK (iOS, Android, JavaScript, PHP, Unity, etc): JS
• SDK version: 2.17.0

Start by reproducing the provided Parse.Query and matchesQuery example on PostgreSQL with null and undefined bar fields, then trace the PostgreSQL handling of the matchesQuery entry point. Compare the result with the expected FILTER behavior and add or update coverage so Foo objects without a matching bar are excluded.