[iOS] Reenable testCloseNTPWhenSwitching omnibox popup test.

Reenables this test. It should now pass.

Fixed: 1037651, 1029255
Change-Id: I982814eb592f227562947fdcd25972885739d1fa
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2574936
Commit-Queue: Stepan Khapugin <stkhapugin@chromium.org>
Reviewed-by: Robbie Gibson <rkgibson@google.com>
Cr-Commit-Position: refs/heads/master@{#833761}

ios/chrome/browser/ui/omnibox/popup/omnibox_popup_egtest.mm

@@ -254,8 +254,7 @@ std::unique_ptr<net::test_server::HttpResponse> StandardResponse(
       assertWithMatcher:grey_nil()];
 }
 
-// TODO(crbug.com/1037651): Test fails.
-- (void)DISABLED_testCloseNTPWhenSwitching {
+- (void)testCloseNTPWhenSwitching {
   // Open the first page.
   GURL URL1 = self.testServer->GetURL(kPage1URL);
   [ChromeEarlGrey loadURL:URL1];