#4395 moved several initial tests from sql_integration into sqllogictests

Specifically, tests that were moved include:

• https://github.com/apache/arrow-datafusion/blob/master/datafusion/core/tests/sql/aggregates.rs --> https://github.com/apache/arrow-datafusion/blob/master/datafusion/core/tests/sqllogictests/test_files/aggregate.slt
• https://github.com/apache/arrow-datafusion/blob/master/datafusion/core/tests/sql/arrow_typeof.rs --> https://github.com/apache/arrow-datafusion/blob/master/datafusion/core/tests/sqllogictests/test_files/arrow_typeof.slt

The goal of this ticket is to:

1. Review that all tests were moved (and none were added subsequently, for example)
2. Port any remaining gaps
3. Remove the .rs files