Bug 1526595 [wpt PR 15260] - Update wpt metadata, a=testonly

wpt-pr: 15260 wpt-type: metadata
2019-02-11 16:00:43 +00:00 · 2019-02-11 16:00:43 +00:00 · 8ec898f6af
--- a/testing/web-platform/meta/domparsing/XMLSerializer-serializeToString.html.ini
+++ b/testing/web-platform/meta/domparsing/XMLSerializer-serializeToString.html.ini
@ -0,0 +1,4 @@
+[XMLSerializer-serializeToString.html]
+  [Check if generated prefixes match to "ns${index}".]
+    expected: FAIL
+