GODRIVER-3013 Resolve race test failures (#1425)

mongo/integration/unified/logger.go

@@ -52,6 +52,9 @@ func newLogger(olm *observeLogMessages, bufSize int) *Logger {
 // Info implements the logger.Sink interface's "Info" method for printing log
 // messages.
 func (log *Logger) Info(level int, msg string, args ...interface{}) {
+	log.orderMu.Lock()
+	defer log.orderMu.Unlock()
+
 	if log.logQueue == nil {
 		return
 	}
@@ -62,9 +65,6 @@ func (log *Logger) Info(level int, msg string, args ...interface{}) {
 		return
 	}
 
-	log.orderMu.Lock()
-	defer log.orderMu.Unlock()
-
 	defer func() { log.lastOrder++ }()
 
 	// Add the Diff back to the level, as there is no need to create a