Optimize CircleCI pipelines (#20933)

Signed-off-by: Mustafa Kara <mustafa.kara@mattermost.com>

build/docker/mysql.conf.d/custom.cnf

@@ -15,5 +15,5 @@ max_connections = 900
 character-set-server = utf8
 sql_mode = ""
 innodb = FORCE
-default-storage-engine = InnoDB
+default-storage-engine = Memory
 max_allowed_packet = 256M

build/docker/postgres.conf

@@ -2,4 +2,6 @@ max_connections = 300
 listen_addresses = '*'
 fsync = off
 full_page_writes = off
-default_text_search_config = 'pg_catalog.english'
+default_text_search_config = 'pg_catalog.english'
+commit_delay=1000
+logging_collector=off