bpo-20369: concurrent.futures.wait() now deduplicates futures given a… (GH-30168)

* bpo-20369: concurrent.futures.wait() now deduplicates futures given as arg.

* 📜🤖 Added by blurb_it.

Co-authored-by: blurb-it[bot] <43283697+blurb-it[bot]@users.noreply.github.com>
(cherry picked from commit 7d7817cf0f826e566d8370a0e974bbfed6611d91)

Co-authored-by: Kumar Aditya <59607654+kumaraditya303@users.noreply.github.com>