remove unnecessary heapcheck suppressions for sync unit tests

tools/heapcheck/suppressions.txt

Index: tools/heapcheck/suppressions.txt
===================================================================
--- tools/heapcheck/suppressions.txt	(revision 95265)
+++ tools/heapcheck/suppressions.txt	(working copy)
@@ -1352,12 +1352,6 @@
    fun:browser_sync::DataTypeManagerImpl::Configure
 }
 {
-   bug_80238
-   Heapcheck:Leak
-   ...
-   fun:sync_notifier::::InvalidationNotifierTest::SetUp
-}
-{
    bug_80467
    Heapcheck:Leak
    ...
@@ -1571,14 +1565,6 @@
    fun:ProfileSyncService*Test::SetUp
 }
 {
-   bug_88438
-   Heapcheck:Leak
-   fun:invalidation::NewPermanentCallback
-   fun:invalidation::InvalidationClientImpl::ScheduleStartAfterReadingStateBlob
-   fun:invalidation::InvalidationClientImpl::Start
-   fun:sync_notifier::ChromeInvalidationClient::Start
-}
-{
    bug_88640
    Heapcheck:Leak
    ...