Auto merge of #104160 - Ayush1325:windows-args, r=m-ou-se

  Extract WStrUnits to sys_common::wstr

This commit extracts WStrUnits from sys::windows::args to sys_common::wstr. This allows using the same structure for other targets which use wtf8 (example UEFI).

This was originally a part of https://github.com/rust-lang/rust/pull/100316

Signed-off-by: Ayush Singh <ayushsingh1325@gmail.com>

diff --cc library/std/src/sys_common/mod.rs
Simple merge