[TokenVesting] Fix test.
[TokenVesting] Fix test.

OpenZeppelin/openzeppelin-contracts,OpenZeppelin/zeppelin-solidity,OpenZeppelin/openzeppelin-contracts,OpenZeppelin/openzeppelin-contracts,OpenZeppelin/zep-solidity,OpenZeppelin/zeppelin-solidity,OpenZeppelin/zep-solidity,pash7ka/zeppelin-solidity,pash7ka/zeppelin-solidity