Make fieldsets work with vertical text.
Basic test (with vendor-prefixes) on legend text position and legend location in vertical-rl writing-mode:
This appears to have been fixed at some point. Close the bug?
Test at https://github.com/web-platform-tests/wpt/pull/12519
(slightly modified and more compact code from the real pull request 12519)
With Epiphany 3.22.7 (WebKit 2.18.6) and with Epiphany Technological Preview 3.29.91-1-g8f26b7ff3 (AppleWebKit/605.1.15; WebKitGTK+ 2.21.5), this appears indeed to have been fixed. I get expected results in all the tests I have.