Disable failing presentation/doc test

I think you are all familiar with the following message from partest:
Discarding invalid test path 'test/files/presentation/doc'

This is fixed in the first commit. Unfortunately, it's failing because of unexpected output:
Got no result
Got no result
Got no result
Got no result
Got no result
Got no result

The expected output is at https://github.com/scala/scala/blob/master/test/files/presentation/doc.check

So, the second commit disables it. If you need an accompanying ticket, I will create it just let me know.