Support 'small-caps' keyword for font-synthesis property

Implement support of 'small-caps' keyword for font-synthethis shorthand
property. Enabled corresponding WPT tests by removing existing fail
expectations.

Bug: 509989
Change-Id: Ib089c2f6742f81eecf471b3c75b46018234939ac
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3168780
Reviewed-by: Dominik Röttsches <[email protected]>
Reviewed-by: Rune Lillesveen <[email protected]>
Commit-Queue: Dominik Röttsches <[email protected]>
Cr-Commit-Position: refs/heads/main@{#923339}

Author: tursunova

css/css-typed-om/the-stylepropertymap/properties/font-synthesis.html

@@ -13,7 +13,7 @@
 <script>
 'use strict';
 
-for (const suffix of ['weight', 'style']) {
+  for (const suffix of ['weight', 'style', 'small-caps']) {
   runPropertyTests('font-synthesis-' + suffix, [
     { syntax: 'auto' },
     { syntax: 'none' },