Async QP performance improvements

resources/log4j.properties

src/metabase/async/semaphore_channel.clj

src/metabase/core.clj

src/metabase/driver.clj

src/metabase/middleware/log.clj

src/metabase/models/database.clj

src/metabase/query_processor.clj

src/metabase/query_processor/middleware/async.clj

src/metabase/query_processor/middleware/async_wait.clj

src/metabase/query_processor/middleware/cache.clj

...ase/query_processor/middleware/process_userland_query.clj

src/metabase/task.clj

test/expectation_options.clj

test/metabase/async/semaphore_channel_test.clj

test/metabase/public_settings_test.clj

test/metabase/query_processor/middleware/async_wait_test.clj

test/metabase/test/util.clj

test/metabase/test_setup.clj