"git diff --stat" used to fully count a binary file with modified
execution bits whose contents is unmodified, which was not right.
By Zbigniew Jędrzejewski-Szmek (4) and Johannes Sixt (1)
* zj/diff-empty-chmod:
t4006: Windows do not have /dev/zero
diff --stat: do not run diff on indentical files
diff --stat: report mode-only changes for binary files like text files
tests: check --[short]stat output after chmod
test: modernize style of t4006