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/common_runtime_test.cc b/runtime/common_runtime_test.cc
index 84752f0..193f6ee 100644
--- a/runtime/common_runtime_test.cc
+++ b/runtime/common_runtime_test.cc
@@ -514,9 +514,9 @@
       soa.Decode<mirror::ClassLoader>(jclass_loader));
 
   DCHECK_EQ(class_loader->GetClass(),
-            soa.Decode<mirror::Class>(WellKnownClasses::dalvik_system_PathClassLoader).Ptr());
+            soa.Decode<mirror::Class>(WellKnownClasses::dalvik_system_PathClassLoader));
   DCHECK_EQ(class_loader->GetParent()->GetClass(),
-            soa.Decode<mirror::Class>(WellKnownClasses::java_lang_BootClassLoader).Ptr());
+            soa.Decode<mirror::Class>(WellKnownClasses::java_lang_BootClassLoader));
 
   // The class loader is a PathClassLoader which inherits from BaseDexClassLoader.
   // We need to get the DexPathList and loop through it.