Bug 1531792 - Enable feature policy and reporting in font-display feature tests r=jgraham

Feature policy is currently only enabled in Nightly. This lets it pass on beta and release.

Differential Revision: https://phabricator.services.mozilla.com/D22397

--HG--
extra : moz-landing-system : lando

testing/web-platform/meta/css/css-fonts/font-display/font-display-feature-policy-report-only.tentative.html.ini

@@ -1,3 +1,4 @@
+prefs: [dom.reporting.enabled:true, dom.reporting.featurePolicy.enabled:true]
 [font-display-feature-policy-report-only.tentative.html]
   expected: TIMEOUT
   [font-display-late-swap Report Format]

testing/web-platform/meta/css/css-fonts/font-display/font-display-feature-policy-reporting.tentative.html.ini

@@ -1,3 +1,4 @@
+prefs: [dom.reporting.enabled:true, dom.reporting.featurePolicy.enabled:true]
 [font-display-feature-policy-reporting.tentative.html]
   expected: TIMEOUT
   [font-display-late-swap Report Format]