Writing Modes: tests for text-combine-upright in horizontal writing modes

`text-combine-upright` does not have effect in horizontal writing modes.
Writing Modes: update style

switch to dated TR/ links to undated TR/ ones. also fix title in reference files.
Writing Modes: move files to css-writing-modes-3 directory

time to move from wip.
Merge pull request #593 from myakura/myakura/tcu-horizontal-modes

LGTM: Writing Modes: tests for text-combine-upright in horizontal writing modes