Merge changes I63514602,Ie0b554e8,Id2549a5a,Ideac7e6a,I20ab0591 into oreo-mr1-cuttlefish-testing

* changes:
  Don't increment the hotness for invokes.
  ART: Remove old aget on null workaround
  ART: Add null type to verifier
  ART: Clean up primitive-type construction
  ART: Add more comprehensive merge test