Fix fast restore - #3608

/cc @TheAngryByrd Please check if this regresses on #2796

Seems to be working for me!

Only issue I seemed to have is having an older FAKE version causes paket.restore.cached to be in a old format and give this new Targets file errors. Might need to recommend people update their FAKE version if they hit this error

.paket/Paket.Restore.targets(101,13): error MSB4184: The expression ""System.String[]".GetValue(1)" cannot be evaluated. Index was outside the bounds of the array.

I think we should fix that, if we cannot read the cache file we should probably call restore and consider it outdated

Seems the testsuite agrees ;)

is this ready?

Should be ready if it turns green. I addressed the failing tests and the issue @TheAngryByrd pointed out (including a test for this scenario as none existed)

Notice that this also fixes fsprojects/FAKE#2348 which apparently is a feature now in the SAFE-Stack. Instead of adding an integration test into FAKE, I think it should be enough that we now have one here, time will tell.

I accidentally pushed into origin and then deleted the branch, therefore we now have 4 instead of 2 CI builds and two are red because they can't find the branch :)

@matthid you always find novel ways to confuse me ;-)

That's why I added a comment ;).
push origin is just to much muscle memory ;)

That's what I do, too terrified I'll flub things up by happenstance

Had to fix another test anyway, so back to normal ;)