ObjPtr<>-ify array allocations.

And remove some unnecessary calls to ObjPtr<>::Ptr().

Test: m test-art-host-gtest
Test: testrunner.py --host --optimizing
Bug: 31113334
Change-Id: Ie313980f7f23b33b0ccea4fa8d5131d643c59080
diff --git a/runtime/reflection.cc b/runtime/reflection.cc
index 66eba1e..6aeedd4 100644
--- a/runtime/reflection.cc
+++ b/runtime/reflection.cc
@@ -243,7 +243,7 @@
         // we've seen cases where it's not b/34440020.
         ObjPtr<mirror::Class> dst_class(
             m->ResolveClassFromTypeIndex(classes->GetTypeItem(args_offset).type_idx_));
-        if (dst_class.Ptr() == nullptr) {
+        if (dst_class == nullptr) {
           CHECK(self->IsExceptionPending());
           return false;
         }