(PUP-1281) Simplify test for wide console behavior

Previously, we were verifying that stdout and stderr were wrapped in WideIO
objects in ruby 1.9. However, this doesn't work in CI, because jenkins
redirects stdout and stderr.

This commit simplifies the test to not be as environmentally sensitive. It
just verifies that the WideConsole and WideIO classes have been defined in
ruby 1.x, and not defined in 2.x.