The `list_preallocate_exact` function did not zero initialize array
contents. In the free-threaded build, this could expose uninitialized
memory to concurrent readers between the call to
`list_preallocate_exact` and the filling of the array contents with
items.

…e-118561.wNMKVd.rst

Co-authored-by: Donghee Na <donghee.na92@gmail.com>