MM-16888: fix missing indexes (#12746)

* MM-16888: fix missing indexes

As part of https://mattermost.atlassian.net/browse/MM-16888, we discovered and fixed a number of column and index mismatches between the canonical (i.e. created from scratch) and migrated schemas (i.e migrated from 5.0 through 5.16).

Unfortunately, the migration to fix same was added to `UpgradeDatabaseToVersion514` but never cherry picked to the pending v5.14 release at the time. Customers who upgraded to v5.14 or v5.15 and then get this code as part of v5.16 will never run that migration. Copy it to the UpgradeDatabaseToVersion516 accordingly.

* avoid fixing ChannelMembers.SchemeGuest on MySQL

* synchronize .circleci/config.yml with scripts/mysql-migration-test.sh

* fix circleci invocation

* additional logging on diff

* update build/Jenkinsfile.pr too!

store/sqlstore/upgrade.go

@@ -713,17 +713,6 @@ func UpgradeDatabaseToVersion513(sqlStore SqlStore) {
 
 func UpgradeDatabaseToVersion514(sqlStore SqlStore) {
 	if shouldPerformUpgrade(sqlStore, VERSION_5_13_0, VERSION_5_14_0) {
-		sqlStore.AlterColumnTypeIfExists("TeamMembers", "SchemeGuest", "tinyint(4)", "boolean")
-		sqlStore.AlterColumnTypeIfExists("ChannelMembers", "SchemeGuest", "tinyint(4)", "boolean")
-		sqlStore.AlterColumnTypeIfExists("Schemes", "DefaultTeamGuestRole", "varchar(64)", "VARCHAR(64)")
-		sqlStore.AlterColumnTypeIfExists("Schemes", "DefaultChannelGuestRole", "varchar(64)", "VARCHAR(64)")
-		sqlStore.AlterColumnTypeIfExists("Teams", "AllowedDomains", "text", "VARCHAR(1000)")
-		sqlStore.AlterColumnTypeIfExists("Channels", "GroupConstrained", "tinyint(1)", "boolean")
-		sqlStore.AlterColumnTypeIfExists("Teams", "GroupConstrained", "tinyint(1)", "boolean")
-
-		sqlStore.CreateIndexIfNotExists("idx_groupteams_teamid", "GroupTeams", "TeamId")
-		sqlStore.CreateIndexIfNotExists("idx_groupchannels_channelid", "GroupChannels", "ChannelId")
-
 		saveSchemaVersion(sqlStore, VERSION_5_14_0)
 	}
 }
@@ -742,5 +731,21 @@ func UpgradeDatabaseToVersion516(sqlStore SqlStore) {
 			sqlStore.GetMaster().Exec("ALTER TABLE Tokens MODIFY Extra text")
 		}
 		saveSchemaVersion(sqlStore, VERSION_5_16_0)
+
+		// Fix mismatches between the canonical and migrated schemas.
+		sqlStore.AlterColumnTypeIfExists("TeamMembers", "SchemeGuest", "tinyint(4)", "boolean")
+		sqlStore.AlterColumnTypeIfExists("Schemes", "DefaultTeamGuestRole", "varchar(64)", "VARCHAR(64)")
+		sqlStore.AlterColumnTypeIfExists("Schemes", "DefaultChannelGuestRole", "varchar(64)", "VARCHAR(64)")
+		sqlStore.AlterColumnTypeIfExists("Teams", "AllowedDomains", "text", "VARCHAR(1000)")
+		sqlStore.AlterColumnTypeIfExists("Channels", "GroupConstrained", "tinyint(1)", "boolean")
+		sqlStore.AlterColumnTypeIfExists("Teams", "GroupConstrained", "tinyint(1)", "boolean")
+
+		// One known mismatch remains: ChannelMembers.SchemeGuest. The requisite migration
+		// is left here for posterity, but we're avoiding fix this given the corresponding
+		// table rewrite in most MySQL and Postgres instances.
+		// sqlStore.AlterColumnTypeIfExists("ChannelMembers", "SchemeGuest", "tinyint(4)", "boolean")
+
+		sqlStore.CreateIndexIfNotExists("idx_groupteams_teamid", "GroupTeams", "TeamId")
+		sqlStore.CreateIndexIfNotExists("idx_groupchannels_channelid", "GroupChannels", "ChannelId")
 	}
 }