Replace handle atomically in IO::FileDescriptor#close on Windows (c…

…rystal-lang#15165)

The spec introduced in crystal-lang#14698 fails on Windows very rarely (e.g. https://github.com/crystal-lang/crystal/actions/runs/11681506288/job/32532033082, https://github.com/crystal-lang/crystal/actions/runs/11642959689/job/32449149741). This PR seems to fix that; other platforms already do the same in `#system_close`, and double close remains an error.

src/crystal/system/win32/file_descriptor.cr

@@ -195,7 +195,11 @@ module Crystal::System::FileDescriptor
   end
 
   def file_descriptor_close(&)
-    if LibC.CloseHandle(windows_handle) == 0
+    # Clear the @volatile_fd before actually closing it in order to
+    # reduce the chance of reading an outdated handle value
+    handle = LibC::HANDLE.new(@volatile_fd.swap(LibC::INVALID_HANDLE_VALUE.address))
+
+    if LibC.CloseHandle(handle) == 0
       yield
     end
   end