Remove PrimitiveArray<T>::array_class_.

And ObjPtr<>-ify jni_internal.cc while we're touching it.

Test: m test-art-host-gtest
Test: testrunner.py --host --optimizing
Bug: 31113334
Change-Id: I15a8ade772e3e4337371c6f3c472f9efea9f4636
7 files changed