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/native/java_lang_Thread.cc b/runtime/native/java_lang_Thread.cc
index a37a76f..13871f7 100644
--- a/runtime/native/java_lang_Thread.cc
+++ b/runtime/native/java_lang_Thread.cc
@@ -119,7 +119,7 @@
     return JNI_FALSE;
   }
   Thread* thread = soa.Self();
-  return thread->HoldsLock(object.Ptr());
+  return thread->HoldsLock(object);
 }
 
 static void Thread_nativeInterrupt(JNIEnv* env, jobject java_thread) {