fuzz with SQLancer

[jayshrivastava]

See #222

We can generate SQL queries using SQLancer https://github.com/datafusion-contrib/datafusion-sqlancer and verify the queries run correctly in distributed datafusion (see property-based validators added in #231)

There's some work to do

• Add arrow flight server for SQLancer to run on
  • Intercept CREATE TABLE and INSERT statements and modify them so we write data to testdata/sqlancer/data
  • Intercept SELECT statements and write them to testdata/sqlancer/queries. Note that queries still need to be executed so SQLancer can use the data to generate more queries (ex. queries on the information scheam table for sure - unclear if it uses normal SELECT queries)
  • Data + queries = fuzz input. We run this input against distributed datafusion and validate using property based tests
• The instructions for sqlancer say to run it with java. We probably need to compile and save a linux sqlancer binary in this repo or in git lfs.

Note that sqlancer does not support nested queries and window functions at the time of writing.