UWP implementations weren't updated for I/O safety

[jdm]

d154185 updated lots of code in library/std/src/sys/windows/ to use the new APIs, but did not modify usages in the conitional UWP implementations like:

• rust/library/std/src/sys/windows/fs.rs

  Line 360 in 47ae8de

  self.handle.raw(),

• https://github.com/rust-lang/rust/blob/master/library/std/src/sys/windows/fs.rs#L388

• rust/library/std/src/sys/windows/stdio_uwp.rs

  Lines 28 to 29 in 47ae8de

  	let handle = Handle::new(handle);
  	ManuallyDrop::new(handle).write(data)

• rust/library/std/src/sys/windows/stdio_uwp.rs

  Lines 41 to 42 in 47ae8de

  	let handle = Handle::new(handle);
  	ManuallyDrop::new(handle).read(buf)

This manifests as a bunch of compile errors when building with --target x86_64-uwp-windows-msvc and -Z build-std.

[apiraino]

Assigning priority as discussed in the Zulip thread of the Prioritization Working Group.

@rustbot label -I-prioritize +P-high

It looks like that #88587 is intended to fix this.