Disable testSucessfullDownloadInIncognito on device.

Bug: 1059320
Change-Id: Ib14a8dd209e277d01b7d2769b2b7ff6da5169f7e
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2091937
Auto-Submit: Eugene But <eugenebut@chromium.org>
Reviewed-by: Sergio Collazos <sczs@chromium.org>
Commit-Queue: Sergio Collazos <sczs@chromium.org>
Cr-Commit-Position: refs/heads/master@{#747837}

ios/chrome/browser/ui/download/download_manager_egtest.mm

@@ -134,7 +134,15 @@ bool WaitForOpenInDownloadsButton() {
 // Tests sucessfull download up to the point where "Open in..." button is
 // presented. EarlGrey does not allow testing "Open in..." dialog, because it
 // is run in a separate process. Performs download in Incognito.
-- (void)testSucessfullDownloadInIncognito {
+#if !TARGET_IPHONE_SIMULATOR
+// TODO(crbug.com/1059320): Test consistently failing on device.
+#define MAYBE_testSucessfullDownloadInIncognito \
+  DISABLED_testSucessfullDownloadInIncognito
+#else
+#define MAYBE_testSucessfullDownloadInIncognito \
+  testSucessfullDownloadInIncognito
+#endif
+- (void)MAYBE_testSucessfullDownloadInIncognito {
   [ChromeEarlGrey openNewIncognitoTab];
   [ChromeEarlGrey loadURL:self.testServer->GetURL("/")];
   [ChromeEarlGrey waitForWebStateContainingText:"Download"];