windows: do not change stdio handle inheritance

This CL stops changing inheritance flag of stdint, stdout and stderr handles.

Fixes golang/go#52498

Change-Id: Ic786f660b457af99a0a975b357c35c36bc7f2b48
Reviewed-on: https://go-review.googlesource.com/c/sys/+/402714
Reviewed-by: Alex Brainman <alex.brainman@gmail.com>
Reviewed-by: Than McIntosh <thanm@google.com>
Reviewed-by: Peter Weinberger <pjw@google.com>
Run-TryBot: Than McIntosh <thanm@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>

windows/syscall_windows.go

@@ -623,7 +623,6 @@ var (
 
 func getStdHandle(stdhandle uint32) (fd Handle) {
 	r, _ := GetStdHandle(stdhandle)
-	CloseOnExec(r)
 	return r
 }