Use 3.0.0-M1 nightly as a reference compiler

[anatoliykmetyuk]

No description provided.

[smarter]

Error: Bad symbolic reference. A signature
Error: refers to Enum/T in package scala.reflect which is not available.

https://github.com/lampepfl/dotty/blob/master/library/src-bootstrapped/scala/reflect/Enum.scala and https://github.com/lampepfl/dotty/blob/master/library/src-bootstrapped/scala/Enum.scala need to be moved to library/src, https://github.com/lampepfl/dotty/blob/master/library/src-non-bootstrapped/scala/Enum.scala needs to be deleted (the same might be true for the other files in src-bootstrapped and src-non-bootstrapped, I don't know if there's some reasons they'd need to stay as is /cc @nicolasstucki)

[smarter]

Also we should bring back 099074c which was blocked on having a new reference compiler.

[nicolasstucki]

I don't see a reason why we should keep Enum.scala split with this update. Moving it to library/src is the right thin to do in this case.

[bishabosha]

I moved the files and rebased

[anatoliykmetyuk]

Thanks a lot @bishabosha!

[smarter]

@nicolasstucki My question was about the other files in src-non-bootstrapped and src-bootstrapped which are all macro-related stuff, should they be moved too?

[nicolasstucki]

No, the macro related stuff should stay

[bishabosha]

so can this be merged?