Bug 1505682 [wpt PR 13977] - grid-template-areas serialization, a=testonly

Automatic update from web-platform-testsgrid-template-areas serialization

strings in grid-template-areas are normalized, e.g. collapsing
whitespace to a single space, and collapsing repeated periods ('.')
to a single period.

https://github.com/w3c/csswg-drafts/issues/3261#issuecomment-436828363

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Merge pull request #13977 from ewilligers/grid-template-areas-serialization-2

grid-template-areas serialization
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wpt-commits: da90a07f543e3307b53230a1f0a2e8b6dc72b42b, a27659a86371bb2d98e622f4e57b85a546898ade
wpt-pr: 13977

testing/web-platform/tests/css/css-grid/parsing/grid-template-areas-valid.html

@@ -19,11 +19,10 @@ test_valid_value("grid-template-areas", '"1st 2nd 3rd"');
 test_valid_value("grid-template-areas", '"first second" "third fourth"');
 test_valid_value("grid-template-areas", '"first second" "third ." "1st 2nd" "3rd 4th"');
 
-// Firefox preserves specific whitespace and full stop sequences.
-// Other browsers consolidate to ' ' and '.'
-test_valid_value("grid-template-areas", '"  a  \t  b  "', '"a b"'); // Fails in Firefox
-test_valid_value("grid-template-areas", '"c\td"', ['"c d"', '"c\\9 d"']);
-test_valid_value("grid-template-areas", '"first ..."', ['"first ."', '"first ..."']);
+// https://github.com/w3c/csswg-drafts/issues/3261
+test_valid_value("grid-template-areas", '"  a  \t  b  "', '"a b"');
+test_valid_value("grid-template-areas", '"c\td"', '"c d"');
+test_valid_value("grid-template-areas", '"first ..."', '"first ."');
 </script>
 </body>
 </html>