Prevent the checked arithmetic cast from nint to void* doesn't cause …

…an OverflowException of 32-bit architectures.

The pre-existing code compiles to:

`new Span<byte>((void*)checked((UIntPtr)handle), _size);`

because CheckForOverflowUnderflow is enabled on the project.

This causes an OverflowException on 32-bit architectures when attempting to perform a checked cast to UIntPtr, likely because the high bit of the 4-byte pointer is set, making it technically a negative number.

src/Interop/Interop.SecureMemoryHandle.cs

@@ -1,4 +1,5 @@
 using System;
+using System.Runtime.CompilerServices;
 using System.Runtime.InteropServices;
 
 internal static partial class Interop
@@ -73,7 +74,7 @@ public void CopyTo(
 
             public unsafe Span<byte> DangerousGetSpan()
             {
-                return new Span<byte>((void*)handle, _size);
+                return new Span<byte>(handle.ToPointer(), _size);
             }
 
             protected override bool ReleaseHandle()