import FIREFOX_52_6_0esr_RELEASE from mozilla-esr52 hg repo

testing/web-platform/tests/conformance-checkers/html-rdfa/0126-isvalid.html

@@ -0,0 +1,12 @@
+<!DOCTYPE html>
+<html prefix="dct: http://purl.org/dc/terms/ sioc: http://rdfs.org/sioc/ns# foaf: http://xmlns.com/foaf/0.1/">
+    <head>
+      <meta charset=utf-8>
+      <title>Test 0126</title>
+    </head>
+    <body>
+      <div about="http://www.example.org/#article" typeof="foaf:Document sioc:Post">
+        <h1 property="dct:title">My article</h1>
+      </div>
+    </body>
+</html>