Merge changes Ifaed1c65,I6ab89e0e,I24f46786,Idcddb109,Iee496c96 into oc-dr1-dev

* changes:
  ART: Change StringTable to unordered_set
  ART: Change StringTable for RecentAllocations
  ART: Presize output vector in RecentAllocations
  ART: Add VLOGs to GetRecentAllocations
  ART: Improve Dbg::GetRecentAllocations