test: add miniClusterMutex to prevent race conditions

- Introduce sync.Mutex to protect global state (os.Args, os.Chdir)
- Ensure serialized initialization of the mini cluster runner
- Fix intermittent race conditions during parallel test execution

test/s3tables/s3tables_integration_test.go

@@ -12,6 +12,8 @@ import (
 	"testing"
 	"time"
 
+	"sync"
+
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
 
@@ -21,6 +23,10 @@ import (
 	flag "github.com/seaweedfs/seaweedfs/weed/util/fla9"
 )
 
+var (
+	miniClusterMutex sync.Mutex
+)
+
 func TestS3TablesIntegration(t *testing.T) {
 	if testing.Short() {
 		t.Skip("Skipping integration test in short mode")
@@ -366,6 +372,10 @@ func startMiniCluster(t *testing.T) (*TestCluster, error) {
 	go func() {
 		defer cluster.wg.Done()
 
+		// Protect global state mutation with a mutex
+		miniClusterMutex.Lock()
+		defer miniClusterMutex.Unlock()
+
 		// Save current directory and args
 		oldDir, _ := os.Getwd()
 		oldArgs := os.Args