This PR removes (most of) the special case pretty printing code in DataFusion's sql integration test, sql.rs in favor of the standard pretty printer in arrow::utils::pretty and in the process adds support for DictionaryArray printing as well as standardizing how tests are run and output is compared.

I am working on adding support for DictionaryArray in DataFusion (and thus want to add tests to sql.rs). This specific PR's changes are larger than strictly necessary, but I felt it made it easier to write new tests in sql.rs. However, if people prefer, I could instead add a special case for DictionaryArray in array_str and accomplish my goal with a much smaller PR

Note: I found that using Vec<Vec<String>> to encode expected results rather than a String retains the nice property that differences to expected output are shown reasonably in the test output. For example:

---- csv_query_cast_literal stdout ----
thread 'csv_query_cast_literal' panicked at 'assertion failed: `(left == right)`
  left: `[["0.9294097332465232", "1.0"], ["0.3114712539863804", "1.0"]]`,
 right: `[["0.9294097332465232", "1"], ["0.3114712539863804", "1"]]`', datafusion/tests/sql.rs:502:5