Testlib console doesn't output to STDOUT on Windows

A testlib exe which used to generate output which can be seen in the visual studio output window built with Qt 5.1.0 does not display the output when built with 5.3.0, and doesn't display any output when run directly as an exe from a normal "DOS" command window.

Though if I run it using the debugger in MSVC then the output does appear in the debug window.

I have a workaround using -o TestFile.txt and displaying the text file. But it sounds like a bug anyway.