[patch, testsuite] skip broken test on Windows

[Nick Clifton]

Hi Sandra,

> It does not diagnose the error if both input and output files have inode 0 (which is what happens on mingw host).  So, instead of producing the expected error, the testcase proceeds to overwrite its input file.  This is bad.  :-(

Ah yes, I had it the wrong way round in my head.  Thanks for clearing it up.

Patch approved - please apply.

Cheers
  Nick