mypy

a0a0ada2 - [mypyc] Refactor: use primitive op for initializing list item (#17056)

[mypyc] Refactor: use primitive op for initializing list item (#17056) Add a new primitive op for initializing list items. Also add support for primitive ops that steal operands (reference counting wise). This will also remove most instances of `WORD_SIZE` in irbuild tests, which were a bit painful, since running tests with `--update-data` removed these and they had to be manually added back for 32-bit tests to pass.