[Extensions] Re-enable TabHighlight test on Windows.

This test was disabled a long time ago. It passed with flying
colors through 3000 iterations on the bots.

Bug: 239022
Change-Id: If83572595b1b75e495796b89a496a099bff913bb
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2264028Reviewed-by: Karan Bhatia <karandeepb@chromium.org>
Commit-Queue: David Bertoni <dbertoni@chromium.org>
Cr-Commit-Position: refs/heads/master@{#784129}

chrome/browser/extensions/extension_tabs_apitest.cc

@@ -113,13 +113,7 @@ IN_PROC_BROWSER_TEST_F(ExtensionApiTabTest, TabQuery) {
   ASSERT_TRUE(RunExtensionSubtest("tabs/basics", "query.html")) << message_;
 }
 
-// Flaky on windows: http://crbug.com/239022
-#if defined(OS_WIN)
-#define MAYBE_TabHighlight DISABLED_TabHighlight
-#else
-#define MAYBE_TabHighlight TabHighlight
-#endif
-IN_PROC_BROWSER_TEST_F(ExtensionApiTabTest, MAYBE_TabHighlight) {
+IN_PROC_BROWSER_TEST_F(ExtensionApiTabTest, TabHighlight) {
   ASSERT_TRUE(RunExtensionSubtest("tabs/basics", "highlight.html")) << message_;
 }