Upgrade golangci-lint to v1.64.5 (#33654)

Use `usetesting` instead of deprecated `tenv`.
1. Follow up #33648
2. Make lint pass and add some comments

modules/util/legacy_test.go

@@ -17,7 +17,7 @@ import (
 func TestCopyFile(t *testing.T) {
 	testContent := []byte("hello")
 
-	tmpDir := os.TempDir()
+	tmpDir := t.TempDir()
 	now := time.Now()
 	srcFile := fmt.Sprintf("%s/copy-test-%d-src.txt", tmpDir, now.UnixMicro())
 	dstFile := fmt.Sprintf("%s/copy-test-%d-dst.txt", tmpDir, now.UnixMicro())