[Kernel] Add some useful asserts

src/xenia/kernel/util/object_table.cc

@@ -194,6 +194,7 @@ X_STATUS ObjectTable::RemoveHandle(X_HANDLE handle) {
   if (entry->object) {
     auto object = entry->object;
     entry->object = nullptr;
+    assert_zero(entry->handle_ref_count);
     entry->handle_ref_count = 0;
 
     // Walk the object's handles and remove this one.

src/xenia/kernel/xobject.cc

@@ -49,6 +49,7 @@ XObject::XObject(KernelState* kernel_state, Type type)
 }
 
 XObject::~XObject() {
+  assert_true(handles_.empty());
   assert_zero(pointer_ref_count_);
 
   if (allocated_guest_object_) {