[Extensions] Enable test that's no longer crashing on ASAN builds.

The BrowserActionApitest.CloseBackgroundPage was disabled in 2011
due to crashing on ASAN builds. I tested this for both regular
Chrome on Linux and ChromeOS builds and it didn't crash after 500
runs.

Bug: 98861
Change-Id: I3c896a4b6231b79fdc47d3be0c3ef3dca7683d49
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1914605Reviewed-by: Karan Bhatia <karandeepb@chromium.org>
Commit-Queue: David Bertoni <dbertoni@chromium.org>
Cr-Commit-Position: refs/heads/master@{#715052}

chrome/browser/extensions/api/extension_action/browser_action_apitest.cc

@@ -700,9 +700,7 @@ IN_PROC_BROWSER_TEST_F(BrowserActionApiTest, IncognitoSplit) {
   ASSERT_TRUE(catcher.GetNextResult()) << catcher.message();
 }
 
-// Disabled because of failures (crashes) on ASAN bot.
-// See http://crbug.com/98861.
-IN_PROC_BROWSER_TEST_F(BrowserActionApiTest, DISABLED_CloseBackgroundPage) {
+IN_PROC_BROWSER_TEST_F(BrowserActionApiTest, CloseBackgroundPage) {
   ASSERT_TRUE(LoadExtension(
       test_data_dir_.AppendASCII("browser_action/close_background")));
   const Extension* extension = GetSingleLoadedExtension();