Executing FindElement or FindElements using free style locator, throws NoSuchElementException

## Reproduce
```csharp
[DataTestMethod]
[DataRow("//div")]
public void AnyLocator(string locator)
{
    // setup
    var element = new MockWebDriver().FindElement(By.XPath(locator));

    // assertion
    Assert.IsTrue(element != null);
}
```

**Expected**: return positive element
**Actual**: throw ```NoSuchElementException```