I needed this icon specifically for a "sort" button which just changes a sort back and forth from asc and desc. I went ahead and created the icon and am using it but wanted to share it incase anyone else thought it was useful or if you wanted to include it with the core icons.

The svg icon:
https://gist.github.com/sebnitu/4a9d9df510b9bfe78118b71f6a2d8568#file-chevrons-up-down-svg

Here are some screenshots: