Remove another JsSyncManagerObserver suppression

Missed this one in r149062.

BUG=139635

Review URL: https://chromiumcodereview.appspot.com/10834091

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@149314 0039d316-1c4b-4281-b951-d872f2087c98

tools/heapcheck/suppressions.txt

@@ -1487,9 +1487,3 @@
    ...
    fun:base::PlatformThread::SetName
 }
-{
-   bug_139635
-   Heapcheck:Leak
-   fun:syncer::JsSyncManagerObserver::OnInitializationComplete
-   fun:syncer::::JsSyncManagerObserverTest_OnInitializationComplete_Test::TestBody
-}