Sort arrow for comments on posts screen wraps strangely

[markjaquith]

Seen:

On hover, it increases the height of the table header.

Expected:

The sort arrow falls to the right, and hover doesn't change the size of the table header.

Probably just need to make that column a tiny bit wider.

Or nowrap the space before it.

This problem does not appear in Firefox, but I can reproduce it in Chrome.

(In [15538]) Fix weird wrapping of sorting arrow in Chrome. Fixes #14706

Turns out that, in Chrome, the padding eats into the column width.