windres PR 33244 testcase

[Maciej W. Rozycki]

On Mon, 4 Aug 2025, Alan Modra wrote:

> Make the windres testing both parse .rc files to binary and back
> again.  It's not possible to compare against the original .rc file
> unfortunately, but at least this checks for the segfault fixed by
> commit 891d1654d731.

 Why not?  We call `cmp' in many test cases, or is the recreated file 
close enough, but not identical to the original here?

  Maciej