Noticed while investigating the test failure in #7123. ``` from matplotlib import dates; from datetime import * plt.plot([datetime(1990, 1, 1), datetime(1990, 1, 1) + timedelta(microseconds=1500)], [0, 0]) plt.show() ``` 1.5.3:  2.0b4:  Note how the horizontal spines are shifted in 2.0b4.
