Fixed a NullReferenceException for F# projects

[psfinaki]

That big LINQ query started to throw for F# since the first cmd-line argument is a tuple (null, null).
In tests, it's enough to just call SourceFiles.

[daveaglick]

Thanks for this! I'll hopefully be able to take a closer look in the next couple days.

[psfinaki]

@daveaglick, sure - thanks :)

[psfinaki]

A very gentle ping for a very small PR :)

[psfinaki]

@safesparrow FYI

[daveaglick]

Done! I know you've been waiting on this, and I didn't really have a chance to review it closely, so I'm trusting the test suite and just YOLO merged. I'll get a release out momentarily.

[psfinaki]

Thanks a lot, Dave :)

[safesparrow]

@safesparrow FYI

What is the PR about? Should I be excited? :)
(I know nothing about the project, besides trying to use it for fsharp cracking)

[psfinaki]

@safesparrow - well just letting you know that I'm also trying to use it for some fsharp cracking :D

NREs are generally not a very exciting matter.