Remove separate compilation tests for pickling blacklist

[nicolasstucki]

Adding new separate compilation is quite annoying because we have to add them all to the pickling blacklist. Moving separate compilation tests to their own folder fixes this issue.

[smarter]

Why do all separate compilation tests need to be in the pickling blacklist?

[nicolasstucki]

I do not remember the details but it was a known issue when @OlivierBlanvillain added the blacklist. The pickling tests framework assumed that all files are compiled together.

[allanrenucci]

Why do all separate compilation tests need to be in the pickling blacklist?

IIRC pickling tests stop after pickling, so separate compilation cannot work since the first compilation does not produce anything

[smarter]

If we get them to output .tasty files that should be enough to get separate compilation working (possibly with some extra stuff from my parallel Dotty PR where I rely on that, cant remember)

[OlivierBlanvillain]

👍

[nicolasstucki]

When we get the extra stuff from the parallel PR in we can just move back this files to run and pos

[nicolasstucki]

Rebased