Revert "Disable SyncUIUtilTest.DistinctCasesReportUniqueMessageSets"

This reverts commit 35279220.

Reason for revert: It looks like all the flakes were caused by unsubmitted code (i.e. pending CLs).

Original change's description:
> Disable SyncUIUtilTest.DistinctCasesReportUniqueMessageSets
> 
> TBR=treib@chromium.org
> 
> Bug: 945628
> Change-Id: I48f13c55991df57c29ae44e3db037b230de3f432
> Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1535655
> Reviewed-by: Tsuyoshi Horo <horo@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#644185}

TBR=horo@chromium.org,treib@chromium.org

# Not skipping CQ checks because original CL landed > 1 day ago.

Bug: 945628
Change-Id: Iab4376dd047c482e43c6ef9105cc339415b3e418
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1541778Reviewed-by: Marc Treib <treib@chromium.org>
Commit-Queue: Marc Treib <treib@chromium.org>
Cr-Commit-Position: refs/heads/master@{#644824}

chrome/browser/sync/sync_ui_util_unittest.cc

@@ -163,8 +163,7 @@ std::unique_ptr<TestingProfile> BuildSignedInTestingProfile() {
 
 // This test ensures that each distinctive SyncService status will return a
 // unique combination of status and link messages from GetStatusLabels().
-// TODO(crbug.com/945628): Disabled due to flakiness.
-TEST_F(SyncUIUtilTest, DISABLED_DistinctCasesReportUniqueMessageSets) {
+TEST_F(SyncUIUtilTest, DistinctCasesReportUniqueMessageSets) {
   std::set<base::string16> messages;
   for (int idx = 0; idx != NUMBER_OF_STATUS_CASES; idx++) {
     std::unique_ptr<Profile> profile = BuildTestingProfile();