Fix order handlers (positive/negative) for new assumptions

Before:
```
In [1]: ask(Q.negative(x**I), Q.positive(x))
Out[1]: False
In [2]: ask(Q.negative((E**(pi/2))**I))
Out[2]: False
In [3]: ask(Q.negative((E**pi)**I))
Out[3]: True
In [4]: ask(Q.positive(1/(1 + x**2)), Q.real(x))
```

After:
```
In [1]: ask(Q.negative(x**I), Q.positive(x))
In [2]: ask(Q.positive(1/(1 + x**2)), Q.real(x))
Out[2]: True
```