[TokenVesting] Remove unnecessary instatiation on test.
[TokenVesting] Remove unnecessary instatiation on test.

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