ObjPtr misc cleanup

Check for subtypes in constructor.

Remove various calls to MakeObjPtr and ObjPtr::Ptr.

Bug: 31113334

Test: test-art-host
Change-Id: I8d680d514ea52cd64fc4f7c2e988926bc726174e
diff --git a/runtime/native/java_lang_reflect_Field.cc b/runtime/native/java_lang_reflect_Field.cc
index 86b42d0..90def44 100644
--- a/runtime/native/java_lang_reflect_Field.cc
+++ b/runtime/native/java_lang_reflect_Field.cc
@@ -46,8 +46,8 @@
   }
   ObjPtr<mirror::Class> calling_class;
   if (!VerifyAccess(self,
-                    MakeObjPtr(obj),
-                    MakeObjPtr(field->GetDeclaringClass()),
+                    obj,
+                    field->GetDeclaringClass(),
                     field->GetAccessFlags(),
                     &calling_class,
                     1)) {
@@ -335,7 +335,7 @@
   ObjPtr<mirror::Object> boxed_value = soa.Decode<mirror::Object>(javaValue);
   JValue unboxed_value;
   if (!UnboxPrimitiveForField(boxed_value,
-                              MakeObjPtr(field_type),
+                              field_type,
                               f->GetArtField(),
                               &unboxed_value)) {
     DCHECK(soa.Self()->IsExceptionPending());