pg_format usage for sql files

There is formatting for C files but test files (sql) are not formatted. Would it make sense to format them with [pg_format](https://github.com/darold/pgFormatter) (and enforce it via a check)? There are a lot of options available with `pg_format` to customize the formatting. You can see some examples of formatted files from this branch(with default options): https://github.com/citusdata/citus/compare/master...SaitTalhaNisanci:use_pyformat?expand=1

I guess this increases the tests readability and there is a uniform formatting across the files with this but then this also changes all test files/ many lines so `blame/history` would show this in many places.