Bug report

Bug summary
The vertices on certain markers ('^', 'D', 'v') are clipped when using plot() to plot data with more than two points and saving the plot as a PDF.

Code for reproduction

import matplotlib.pyplot as plt
size = 256, 16
fig,ax = plt.subplots()
num = 3

fig,ax = plt.subplots()
ax.plot([i+1 for i in range(num)],[1 for i in range(num)], '^', markersize=3, markeredgewidth=0.7, color='green', markeredgecolor='black')
ax.set_xlim(0, num +1)
ax.set_xticks(())
ax.set_yticks(())
fig.savefig('test.pdf') # This doesn't work properly.
fig.savefig('test.svg')

Actual outcome

The top image is of the marker from the .pdf file. The bottom image is of the marker from the .svg file.

Expected outcome

The marker in the .pdf file should look like the marker in the .svg file.

Matplotlib version

• Operating system: Ubuntu 17.04
• Matplotlib version: 2.1.0
• Matplotlib backend (print(matplotlib.get_backend())): TkAgg
• Python version: Python 3.5.3
• Jupyter version (if applicable):
• Other libraries:

I installed matplotlib via pip.