Bug 1387007 - Disable site data clearing test that causes subsequent tests to fail, a=testonly

MozReview-Commit-ID: 77OeStIjLNm

testing/web-platform/meta/clear-site-data/navigation.https.html.ini

@@ -1,7 +1,7 @@
 [navigation.https.html]
   type: testharness
   expected: TIMEOUT
-  disabled: true
+  disabled: https://bugzilla.mozilla.org/show_bug.cgi?id=1387007
   [Clear datatypes on navigation: cookies]
     expected: TIMEOUT