The ClearSymbols fixture erases all symbols created by
Symbol Handlers.
| check | test result |
| string |
| field | field? |
| hello | >>mysymbol |
| <<mysymbol | hello |
| string |
| field | field? |
| <<mysymbol | null |
| | string | | field | field? | | hello | hello >>mysymbol | | hello <<mysymbol | hello |
| string | | field | field? | | null <<mysymbol | null |
|