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/compiler/dex/dex_to_dex_decompiler_test.cc b/compiler/dex/dex_to_dex_decompiler_test.cc
index 75de238..1fe42ad 100644
--- a/compiler/dex/dex_to_dex_decompiler_test.cc
+++ b/compiler/dex/dex_to_dex_decompiler_test.cc
@@ -67,7 +67,7 @@
       class_loader = LoadDex(dex_name);
       updated_dex_file = GetDexFiles(class_loader)[0];
       Runtime::Current()->GetClassLinker()->RegisterDexFile(
-          *updated_dex_file, soa.Decode<mirror::ClassLoader>(class_loader).Ptr());
+          *updated_dex_file, soa.Decode<mirror::ClassLoader>(class_loader));
     }
     // The dex files should be identical.
     int cmp = memcmp(original_dex_file->Begin(),