* Reuse connection for test data loading & JDBC data loading overhaul

* Revert silly change

* Remove unneeded logic for recording which datasets are loaded or not-yet-loaded

* Ok so I guess we do need the code to detect duplicate dataset loading after all

* B I G  improvements

* Appease Kondo

* Test fixes 

* More test fixes 

* Fix dataset-already-loaded?-test

* Fix test

* Fix Presto JDBC and greatly improve test data load speed for it

* Postgres test fix 

* Fix compilation errors

* MySQL fixes 

* Fix syntax error

* MySQL fixes 

* Implement `dataset-already-loaded?` for Athena and cache the set of existing databases

* Fix Redshift

* Fix Presto JDBC

* Vertica test fix 

* Fix Oracle dataset-already-loaded?

* Test fixes and parallelize some API tests.

* Test fixes 

* Oracle test fix? 

* Another test fix 

* Stop putting random spaces in code bodies this is not JavaScript code

* with-temp-vals-in-db should merge in original value of Database settings

* The most test fixes 

* 3 or 4 test fixes 

* Add schemas around stuff to catch errors

* Appease Kondo

* Implement dataset-already-loaded? for vertica

* Implement dataset-already-loaded? for SQLite and Snowflake

* Redshift: drop session schema when test suite finishes [ci skip]

* Update Hawk version

* PR feedback

* Bump Hawk version

* Skip after-run for drivers that don't have test extensions

---------

Co-authored-by: Cal Herries <39073188+calherries@users.noreply.github.com>

Upgrade Liquibase to latest version; remove final Java source file and need for `clojure -X:deps prep` (#20611)

* Upgrade Liquibase to latest version

* Try adjusting log

* Fix checksums for the TWO migrations with ID = 32

* FINALLY get Liquibase to use Log4j2

* Set Liquibase ConsoleUIService OutputStream to null OutputStream

* Manually define a package for our H2 proxy class so Java 8 works

* Fix package-name determination code

* Update migrations file spec

* `databasechangelog` shouldn't be upper-case

* Lower-case quartz table names

* More MySQL fixes 

* Properties for all the Quartz tables 

* Formatting tweaks [ci skip]

* Revert a few more busted changes

* Fix more busted changes

* Bump Liquibase version to 4.8.0 to fix MySQL defaultValueBoolean bug

* OMG I think I finally fixed MySQL

* Remove Java source file and prep-deps code

* Remove two more references to bin/prep.sh

* Minor cleanup

* Revert unneeded changes

* Fix busted indentation

* Don't search inside java/ anymore since it's G-O-N-E

* Appease the namespace linter

* Update src/metabase/db/liquibase/h2.clj

* Fix logging utils

* Test fixes 

* Fix noisy logs in tests

* Fix lint error

* Fix Google driver build [ci bigquery]

* Tweak chain filter tests

* Fix i18n tag

* Fix database sync test (maybe)

* Add u/decolorize for latest JUnit output tweak

* Fix 

* Test fix 

* Upgrade to log4j 2.13.3

Upgrades us to newer Log4j

Resolves #12719

* fixing reflection warnings

* reflection warning on test

* make tests work

took a while to figure out how to configure log4j properly
programatically - it's not as easy as log4j 1

add logging adapters for commons-logging, slf4j, liquibase, etc so that
all logging routes through log4j2 now

* appease the linters

* okay cljr-clean-ns makes this line too long, I get it

* add log4j2.xml config for Cypress tests

* update log4j configuration file documentation

update which flag is used by the backend tests

[ci all]

* update cheshire because clj-http updated

* Wire up the metabase-appender to Log4j2

This was brutal to figure out - log4j usually silently fails, so it took
finding the right combination of configuration settings and system
properties to get it to log enough to find out why the appender was
never invoked.