message: fix(account-lib): fix validity windows unit test
  fix validity windows unit test
diff: @@ -137,9 +137,10 @@ describe('Transaction builder', () => {
  params = {
  unit: 'timestamp',
  };
  + const dateNow = Date.now();
  validityWindow = txBuilder.getValidityWindow(params);
  validityWindow.should.have.properties(['firstValid', 'lastValid', 'minDuration', 'maxDuration', 'unit']);
  - validityWindow.firstValid.should.be.greaterThanOrEqual(Date.now());
  + validityWindow.firstValid.should.be.greaterThanOrEqual(dateNow);
  validityWindow.lastValid.should.be.equal(validityWindow.firstValid + 31536000000);
  validityWindow.minDuration.should.be.equal(0);
  validityWindow.maxDuration.should.be.equal(31536000000);
  