I was concerned for a little bit that passing just whitespace to the
split_html_space_chars function would result in len > 0, so I wrote this
small unit test to make sure it does the right thing. Even though it
does do the right thing, I think there's still value in committing the
unit test.
Source-Repo: https://github.com/servo/servo
Source-Revision: d3d4976d8ed7cd7e92a1246513e125d1a6093d2a
