test: use `T.TempDir` to create temporary test directory (#21043)

A testing cleanup. 

This pull request replaces `os.MkdirTemp` with `t.TempDir`. We can use the `T.TempDir` function from the `testing` package to create temporary directory. The directory created by `T.TempDir` is automatically removed when the test and all its subtests complete. 

This saves us at least 2 lines (error check, and cleanup) on every instance, or in some cases adds cleanup that we forgot.

Reference: https://pkg.go.dev/testing#T.TempDir

```go
func TestFoo(t *testing.T) {
	// before
	tmpDir, err := os.MkdirTemp("", "")
	require.NoError(t, err)
	defer os.RemoveAll(tmpDir)

	// now
	tmpDir := t.TempDir()
}
```

Signed-off-by: Eng Zer Jun <engzerjun@gmail.com>

2 files changed, 3 insertions, 14 deletions

diff --git a/modules/queue/queue_disk_channel_test.go b/modules/queue/queue_disk_channel_test.go
index 22b4f0f452..b1820e73ac 100644
--- a/modules/queue/queue_disk_channel_test.go
+++ b/modules/queue/queue_disk_channel_test.go
@@ -5,13 +5,11 @@
 package queue
 
 import (
-	"os"
 	"sync"
 	"testing"
 	"time"
 
 	"code.gitea.io/gitea/modules/log"
-	"code.gitea.io/gitea/modules/util"
 
 	"github.com/stretchr/testify/assert"
 )
@@ -33,9 +31,7 @@ func TestPersistableChannelQueue(t *testing.T) {
 	queueShutdown := []func(){}
 	queueTerminate := []func(){}
 
-	tmpDir, err := os.MkdirTemp("", "persistable-channel-queue-test-data")
-	assert.NoError(t, err)
-	defer util.RemoveAll(tmpDir)
+	tmpDir := t.TempDir()
 
 	queue, err := NewPersistableChannelQueue(handle, PersistableChannelQueueConfiguration{
 		DataDir:      tmpDir,
@@ -223,9 +219,7 @@ func TestPersistableChannelQueue_Pause(t *testing.T) {
 	queueTerminate := []func(){}
 	terminated := make(chan struct{})
 
-	tmpDir, err := os.MkdirTemp("", "persistable-channel-queue-pause-test-data")
-	assert.NoError(t, err)
-	defer util.RemoveAll(tmpDir)
+	tmpDir := t.TempDir()
 
 	queue, err = NewPersistableChannelQueue(handle, PersistableChannelQueueConfiguration{
 		DataDir:      tmpDir,
diff --git a/modules/queue/queue_disk_test.go b/modules/queue/queue_disk_test.go
index d2d8e135cb..b0835c896f 100644
--- a/modules/queue/queue_disk_test.go
+++ b/modules/queue/queue_disk_test.go
@@ -5,13 +5,10 @@
 package queue
 
 import (
-	"os"
 	"sync"
 	"testing"
 	"time"
 
-	"code.gitea.io/gitea/modules/util"
-
 	"github.com/stretchr/testify/assert"
 )
 
@@ -30,9 +27,7 @@ func TestLevelQueue(t *testing.T) {
 	queueShutdown := []func(){}
 	queueTerminate := []func(){}
 
-	tmpDir, err := os.MkdirTemp("", "level-queue-test-data")
-	assert.NoError(t, err)
-	defer util.RemoveAll(tmpDir)
+	tmpDir := t.TempDir()
 
 	queue, err := NewLevelQueue(handle, LevelQueueConfiguration{
 		ByteFIFOQueueConfiguration: ByteFIFOQueueConfiguration{