BLD: Remove windows shim
Just to see if this breaks the world.
> Just in case, I think it would be good to include a whatsnew note that a customs header for int types for VS 2019 compat has been removed.

I don't see how it's user-facing, but OK.  Suggested wording/location? Okay on second thought, this should be okay. Thanks @jbrockmendel  ~Looks like this also fixed the py38_32bit build.~

Nevermind, the run was from before this build started failing.