[alreq] Text opacity shows glyph overlap (#221)

r12a has just created a new issue for https://github.com/w3c/alreq:

== Text opacity shows glyph overlap ==
When opacity is applied to text,  <span class="fail">Firefox</span> and <span class="fail">Chrome</span> produce dark patches where the cursive glyphs overlap, but <span class="pass">Safari</span> and <span class="pass">Edge</span> don't. See the <a href="https://w3c.github.io/i18n-tests/results/cursive#text_opacity">test</a>.

![text-opacity](https://user-images.githubusercontent.com/4839211/73611382-2c334a00-45d9-11ea-8c5a-eb3a496c8b24.png)


Please view or discuss this issue at https://github.com/w3c/alreq/issues/221 using your GitHub account