refactor: only reset a database table when the table's data was changed (#37573)

Reduce CI time

Saves about 3 minutes for each test suit

test-unit: 13min -> 10min (-race)
test-pgsql: 24min -> 20min (-race)
test-mysql: 15min -> 12min
test-mssql: 16min -> 12min

---------

Co-authored-by: silverwind <me@silverwind.io>
Co-authored-by: Claude (Opus 4.7) <noreply@anthropic.com>

tests/test_utils.go

@@ -36,6 +36,7 @@ func InitIntegrationTest() error {
 		return err
 	}
 
+	setting.Database.SlowQueryThreshold = 0
 	setting.LoadDBSetting()
 	cleanupDb, err := unittest.ResetTestDatabase()
 	if err != nil {