Remove the unused #ifdef and #includes related to the old Cocoa-on-Windows libraries.
<rdar://problem/105192076>
Pull request: https://github.com/WebKit/WebKit/pull/9837
Committed 260076@main (1154eb41e9f8): <https://commits.webkit.org/260076@main> Reviewed commits have been landed. Closing PR #9837 and removing active labels.