Move mirror::ObjectArray to ObjPtr

Also reduce calls to ObjPtr::Ptr.

Bug: 31113334

Test: test-art-host -j32

Change-Id: I73e1b356972bb079b66332f00f7f07451601044e
diff --git a/runtime/entrypoints/quick/quick_trampoline_entrypoints.cc b/runtime/entrypoints/quick/quick_trampoline_entrypoints.cc
index 126e26c..750efac 100644
--- a/runtime/entrypoints/quick/quick_trampoline_entrypoints.cc
+++ b/runtime/entrypoints/quick/quick_trampoline_entrypoints.cc
@@ -834,7 +834,7 @@
 void BuildQuickArgumentVisitor::FixupReferences() {
   // Fixup any references which may have changed.
   for (const auto& pair : references_) {
-    pair.second->Assign(soa_->Decode<mirror::Object>(pair.first).Ptr());
+    pair.second->Assign(soa_->Decode<mirror::Object>(pair.first));
     soa_->Env()->DeleteLocalRef(pair.first);
   }
 }
@@ -926,7 +926,7 @@
 void RememberForGcArgumentVisitor::FixupReferences() {
   // Fixup any references which may have changed.
   for (const auto& pair : references_) {
-    pair.second->Assign(soa_->Decode<mirror::Object>(pair.first).Ptr());
+    pair.second->Assign(soa_->Decode<mirror::Object>(pair.first));
     soa_->Env()->DeleteLocalRef(pair.first);
   }
 }