Added 15 widows & orphans tests and 14 references: content distribution in columns

[TalbotG]

15 tests testing various 'widows' and 'orphans' values in multi-column container with 'column-fill: auto' , all testing content distribution among column boxes.

The first set of tests (-022 to -027) have the multi-column container's 'height' set to 'auto'.

The tests -028 and -029 have not been included in this PR on purpose: they represent an edge or unclear code scenarios not covered by the spec. They may eventualy be submitted as a spec issue..
[Edit]
I have figured out what was wrong with my initial, original version of tests -028 and -029. I will include in a few days a revised and improved version of tests -029 and -029.
[/Edit]

The second set of tests (-032 to -039) have the multi-column container's 'height' set to '104px' or to a taller non-auto value.

The -041 test is actually the same test as -022 but it uses 'widows: initial'. The interesting thing about -041 test is that Epiphany version 3.32.1.2 (WebKitGTK+ 2.30.3) passes -022 but fails -041 ... which is somehow incoherent and illogical.
Chromium 83.0.4103.116 passes both -022 and -041 tests.

On my website, the tests and reference files are:

http://www.gtalbot.org/BrowserBugsSection/CSS3Break/widows-orphans-022.html
http://www.gtalbot.org/BrowserBugsSection/CSS3Break/reference/widows-orphans-022-ref.html

http://www.gtalbot.org/BrowserBugsSection/CSS3Break/widows-orphans-023.html
http://www.gtalbot.org/BrowserBugsSection/CSS3Break/reference/widows-orphans-023-ref.html

http://www.gtalbot.org/BrowserBugsSection/CSS3Break/widows-orphans-024.html
http://www.gtalbot.org/BrowserBugsSection/CSS3Break/reference/widows-orphans-024-ref.html

http://www.gtalbot.org/BrowserBugsSection/CSS3Break/widows-orphans-025.html
http://www.gtalbot.org/BrowserBugsSection/CSS3Break/reference/widows-orphans-025-ref.html

http://www.gtalbot.org/BrowserBugsSection/CSS3Break/widows-orphans-026.html
http://www.gtalbot.org/BrowserBugsSection/CSS3Break/reference/widows-orphans-026-ref.html

http://www.gtalbot.org/BrowserBugsSection/CSS3Break/widows-orphans-027.html
http://www.gtalbot.org/BrowserBugsSection/CSS3Break/reference/widows-orphans-027-ref.html

http://www.gtalbot.org/BrowserBugsSection/CSS3Break/widows-orphans-032.html
http://www.gtalbot.org/BrowserBugsSection/CSS3Break/reference/widows-orphans-032-ref.html

http://www.gtalbot.org/BrowserBugsSection/CSS3Break/widows-orphans-033.html
http://www.gtalbot.org/BrowserBugsSection/CSS3Break/reference/widows-orphans-033-ref.html

http://www.gtalbot.org/BrowserBugsSection/CSS3Break/widows-orphans-034.html
http://www.gtalbot.org/BrowserBugsSection/CSS3Break/reference/widows-orphans-034-ref.html

http://www.gtalbot.org/BrowserBugsSection/CSS3Break/widows-orphans-035.html
http://www.gtalbot.org/BrowserBugsSection/CSS3Break/reference/widows-orphans-035-ref.html

http://www.gtalbot.org/BrowserBugsSection/CSS3Break/widows-orphans-036.html
http://www.gtalbot.org/BrowserBugsSection/CSS3Break/reference/widows-orphans-036-ref.html

http://www.gtalbot.org/BrowserBugsSection/CSS3Break/widows-orphans-037.html
http://www.gtalbot.org/BrowserBugsSection/CSS3Break/reference/widows-orphans-037-ref.html

http://www.gtalbot.org/BrowserBugsSection/CSS3Break/widows-orphans-038.html
http://www.gtalbot.org/BrowserBugsSection/CSS3Break/reference/widows-orphans-038-ref.html

http://www.gtalbot.org/BrowserBugsSection/CSS3Break/widows-orphans-039.html
http://www.gtalbot.org/BrowserBugsSection/CSS3Break/reference/widows-orphans-039-ref.html

http://www.gtalbot.org/BrowserBugsSection/CSS3Break/widows-orphans-041.html
http://www.gtalbot.org/BrowserBugsSection/CSS3Break/reference/widows-orphans-022-ref.html

[mstensho]

Thank you for working on this! We need better test coverage for orphans and widows.

Can you start counting from 006 instead of 022, though? css/css-break/widows-orphans-005.html is the last test that got added.

[mstensho]

Can use link rel="help" instead.

[TalbotG]

"Bug 137367 ..." is not a related spec resource or content.
When tests were XHTML1 or HTML4 declared, I could use
the rel attribute value "bookmark". I can no longer do that
in HTML5.

[wpt-pr-bot]

There are no reviewers for this pull request. Please reach out on W3C's irc server (irc.w3.org, port 6665) on channel #testing (web client) to get help with this. Thank you!

[TalbotG]

On my website, the tests and reference files are:

http://www.gtalbot.org/BrowserBugsSection/CSS3Break/widows-orphans-008.html
http://www.gtalbot.org/BrowserBugsSection/CSS3Break/reference/widows-orphans-008-ref.html

http://www.gtalbot.org/BrowserBugsSection/CSS3Break/widows-orphans-009.html
http://www.gtalbot.org/BrowserBugsSection/CSS3Break/reference/widows-orphans-009-ref.html

http://www.gtalbot.org/BrowserBugsSection/CSS3Break/widows-orphans-010.html
http://www.gtalbot.org/BrowserBugsSection/CSS3Break/reference/widows-orphans-010-ref.html

http://www.gtalbot.org/BrowserBugsSection/CSS3Break/widows-orphans-011.html
http://www.gtalbot.org/BrowserBugsSection/CSS3Break/reference/widows-orphans-011-ref.html

http://www.gtalbot.org/BrowserBugsSection/CSS3Break/widows-orphans-012.html
http://www.gtalbot.org/BrowserBugsSection/CSS3Break/reference/widows-orphans-012-ref.html

http://www.gtalbot.org/BrowserBugsSection/CSS3Break/widows-orphans-013.html
http://www.gtalbot.org/BrowserBugsSection/CSS3Break/reference/widows-orphans-013-ref.html

http://www.gtalbot.org/BrowserBugsSection/CSS3Break/widows-orphans-014.html
http://www.gtalbot.org/BrowserBugsSection/CSS3Break/reference/widows-orphans-014-ref.html

http://www.gtalbot.org/BrowserBugsSection/CSS3Break/widows-orphans-015.html
http://www.gtalbot.org/BrowserBugsSection/CSS3Break/reference/widows-orphans-016-ref.html

http://www.gtalbot.org/BrowserBugsSection/CSS3Break/widows-orphans-016.html
http://www.gtalbot.org/BrowserBugsSection/CSS3Break/reference/widows-orphans-016-ref.html

http://www.gtalbot.org/BrowserBugsSection/CSS3Break/widows-orphans-017.html
http://www.gtalbot.org/BrowserBugsSection/CSS3Break/reference/widows-orphans-017-ref.html

---

height: 104px and orphans = 1 and widows = 3: widows-orphans-008.html

height: 104px and orphans = 2 and widows = 2: widows-orphans-009.html

height: 104px and orphans = 2 and widows = 3: widows-orphans-010.html

height: 156px and orphans = 2 and widows = 6: widows-orphans-011.html

height: 208px and orphans = 3 and widows = 7: widows-orphans-012.html

height: 234px and orphans = 6 and widows = 4: widows-orphans-013.html

height: 234px and orphans = 7 and widows = 3: widows-orphans-014.html

height: 104px and orphans = 1 and widows = initial: widows-orphans-015.html

height: 104px and orphans = 1 and widows = 2: widows-orphans-016.html

height: auto and orphans = 1 and widows = 2: widows-orphans-017.html