investigate cygwin failures

[wchristian]

On David Solimano's smoker that test fails in a curious manner. I have three theories as to how that may be:

• [ ] he has an os version that allows perms to be ignored (win server or something)
• [ ] he is running as a user that has elevated accesses
• [ ] the chmod return value is bogus and the perms don't actually change
• [ ] the test actually finds entirely unrelated data

The attached commits update the file perm test to add more debug output, and to check the chmod result by looking at the file perms directly, ignoring the chmod return value. (Might actually need some autodie too.)

[hoelzro]

Thanks again!

[petdance]

Can't use autodie. It's not core until 5.10.1.