Bug 1415805 - enable webvtt/paring/file-parsing/tests/region-old.html. r=rillian

MozReview-Commit-ID: 1G9Fd9sEW9x

--HG--
extra : rebase_source : fddb496b5ba5cee178efeedd29565bf45951d3ec

testing/web-platform/meta/webvtt/parsing/file-parsing/tests/regions-old.html.ini

@@ -1,5 +1,5 @@
 [regions-old.html]
   type: testharness
   [regions, old]
-    expected: FAIL
+    expected: PASS