The retained-reference regression exercised generic message pointer
behavior but lived in the one-shot actor API suite and combined an
unrelated public trampoline alias assertion.
Move the pointer regression into a focused message-layer test module
and retain the alias contract as its own `to_actor` API test.
Review: PR #481 (goodboy)
https://github.com/goodboy/tractor/pull/481#pullrequestreview-5012942328
(this patch was generated in some part by `opencode` using `gpt-5.6-sol` (`openai`))