An `askReload` made on a file that is dead for some reason has the risk of making it a zombie. Every occasion to do it  is good. 

In this case that makes specific sense, because the first thing done when removing a file is eliminating it from the underlying `unitOfFile` map, which is also the place `compilationUnits` acts on. As soon as this removal is done, scheduling a reload on that same file (without e.g. re-opening the file) should be invalid.

Finally, I may have overlooked something but I was under the impression `compilationUnits` containing a lot of units was far from our use case (and is likely to remain far in the future).