[3.12] gh-128696: Add arm64 to the get_platform return val description (GH-128701) (#128773)

gh-128696: Add arm64 to the get_platform return val description (GH-128701)
(cherry picked from commit 553cdc6d6856c1b4539a45eb90d0769f7c629355)

Co-authored-by: RUANG (James Roy) <longjinyii@outlook.com>