test: use T.TempDir to create temporary test directory

The directory created by `T.TempDir` is automatically removed when the
test and all its subtests complete.

Reference: https://pkg.go.dev/testing#T.TempDir
Signed-off-by: Eng Zer Jun <engzerjun@gmail.com>

weed/storage/volume_write_test.go

@@ -2,7 +2,6 @@ package storage
 
 import (
 	"fmt"
-	"os"
 	"testing"
 	"time"
 
@@ -12,11 +11,7 @@ import (
 )
 
 func TestSearchVolumesWithDeletedNeedles(t *testing.T) {
-	dir, err := os.MkdirTemp("", "example")
-	if err != nil {
-		t.Fatalf("temp dir creation: %v", err)
-	}
-	defer os.RemoveAll(dir) // clean up
+	dir := t.TempDir()
 
 	v, err := NewVolume(dir, dir, "", 1, NeedleMapInMemory, &super_block.ReplicaPlacement{}, &needle.TTL{}, 0, 0)
 	if err != nil {