Bug 1409359 - Cleanup installed add-on in testExtensionControlledNewTab r=aswan,bsilverberg

MozReview-Commit-ID: B9GKuyvPWNd

--HG--
extra : rebase_source : 07140c9189c8f278f9526d4b12ea27a5afff6088

browser/components/preferences/in-content/tests/browser_extension_controlled.js

@@ -274,6 +274,8 @@ add_task(async function testExtensionControlledNewTab() {
   is(controlledContent.hidden, true, "The extension controlled row is hidden");
 
   await BrowserTestUtils.removeTab(gBrowser.selectedTab);
+  let addon = await AddonManager.getAddonByID("@set_newtab");
+  addon.uninstall();
 });
 
 add_task(async function testExtensionControlledHomepageUninstalledAddon() {