Replace Unsafe constants with Slice SizeOf
Minor formatter cleanup
Make visitor methods protected
Fix SQL formatter

This fixes the formatting of explicit TABLE queries and adds missing
formatters for certain constructs:

* UNION, EXCEPT, INTERSECT
* DROP TABLE
* APPROXIMATE AT

Additionally, every local test query is verfied to round-trip.
Remove sampled exact aggregation tests
Remove sampled benchmarks
Fix intellij warning
Remove bootstrapped aggregation
Refactor aggregations

Introduce a new base class for aggregation functions that makes them
simpler to write.
Add missing presto-main dependency to presto-server

This was missed in the refactoring that moved the server code to presto-main.
As a result, the server fails to start when run via the launcher
Replace Unsafe with new Slice ByteArrays utility
Remove obsolete TODO
Set 1 hour time bound on model training
Remove heuristic from learn aggregation
Add unit test for learn aggregation
Add function to train libsvm models

Add special learning functions that allow you to configure the
hyperparameters of the model
Fix Hive tests for VARBINARY
Fix hidden columns in union planning