Fairswap: inconsistent checks on _executionOrder()
The `_executionOrder()` function should only be called under specific conditions. However, these conditions are not always consistently defined.\\n```\\nif (nextBoxNumber > 1 && nextBoxNumber > nextExecuteBoxNumber) {\\n```\\n\\n```\\nif (nextBoxNumber > 1 && nextBoxNumber > nextExecuteBoxNumber) {\\n```\\n\\n```\\nif (nextBoxNumber > 1 && nextBoxNumber >= nextExecuteBoxNumber) {\\n```\\n
Resolution\\nComment from Lien Protocol:\\nReduce duplicate code by defining an internal function to perform this check. A clear, descriptive name will help to clarify the intention.
```\\nif (nextBoxNumber > 1 && nextBoxNumber > nextExecuteBoxNumber) {\\n```\\n