Refactor tests (#33021)

1. fix incorrect tests, for example: BeanExists doesn't do assert and
shouldn't be used
2. remove unnecessary test functions
3. introduce DumpQueryResult to help to see the database rows during
test (at least I need it)

```
====== DumpQueryResult: SELECT * FROM action_runner_token ======
- # row[0]
  id: 1
  token: xeiWBL5kuTYxGPynHCqQdoeYmJAeG3IzGXCYTrDX
  owner_id: 0
...
```

models/unittest/testdb.go

@@ -34,11 +34,6 @@ var (
 	fixturesDir string
 )
 
-// FixturesDir returns the fixture directory
-func FixturesDir() string {
-	return fixturesDir
-}
-
 func fatalTestError(fmtStr string, args ...any) {
 	_, _ = fmt.Fprintf(os.Stderr, fmtStr, args...)
 	os.Exit(1)