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>

1 files changed, 3 insertions, 6 deletions

diff --git a/tests/integration/lfs_local_endpoint_test.go b/tests/integration/lfs_local_endpoint_test.go
index 88c08c63db..4042dc95b3 100644
--- a/tests/integration/lfs_local_endpoint_test.go
+++ b/tests/integration/lfs_local_endpoint_test.go
@@ -25,15 +25,12 @@ func str2url(raw string) *url.URL {
 func TestDetermineLocalEndpoint(t *testing.T) {
 	defer tests.PrepareTestEnv(t)()
 
-	root, _ := os.MkdirTemp("", "lfs_test")
-	defer os.RemoveAll(root)
+	root := t.TempDir()
 
-	rootdotgit, _ := os.MkdirTemp("", "lfs_test")
-	defer os.RemoveAll(rootdotgit)
+	rootdotgit := t.TempDir()
 	os.Mkdir(filepath.Join(rootdotgit, ".git"), 0o700)
 
-	lfsroot, _ := os.MkdirTemp("", "lfs_test")
-	defer os.RemoveAll(lfsroot)
+	lfsroot := t.TempDir()
 
 	// Test cases
 	cases := []struct {