Greek text-transform tests

[r12a]

@LeaVerou @svgeesus
The test at https://w3c.github.io/i18n-tests/css-text/text-transform/text-transform-upperlower-035.html is problematic in 2 ways:

1. Ϊ́̈ is a clear bug
2. the test includes many Latin characters besides Greek

It would also be more helpful to group the other Greek tests together and arrange them according to the ways case conversion is used for Greek, rather than by the Unicode algorithms.

I have begun making new tests at https://w3c.github.io/i18n-tests/run?base=css-text/text-transform&batch=case-conversion (click on Next to advance through the tests).

I'll also consider creating small caps tests.

[r12a]

Ok, tests are in place for monotonic Greek. Polytonic still needs to be done (which will involve special tests for the iota diphthongs).

Results are also available, at https://w3c.github.io/i18n-tests/results/case-conversion

Notice that specifying the language of the text as el is vital for correct conversions of vowels!

[svgeesus]

Interesting new tests. In Firefox I see some failures in
https://w3c.github.io/i18n-tests/css-text/text-transform/greek/text-transform-uc-el-monotonic-vowels-exp.html
because the tonos is dropped.

[r12a]

Indeed. Note that that's an exploratory test (see the results page at https://w3c.github.io/i18n-tests/results/case-conversion), and a useful one, since it's showing that the language declaration is crucial to good results. (Fwiw, exploratory tests don't get ported to WPT.)