Also rename orphan_state to state. Both the comment and the variable
name are leftover from when this logic was part of ProcessMessage().
This is a backport of [[https://github.com/bitcoin/bitcoin/pull/19498 | core#19498]] [4/5]
https://github.com/bitcoin/bitcoin/pull/19498/commits/e07c5d94231cefb748f9534ab8ff0b3e2b04c4d8
Depends on D10414