We should disable the --multiemit[+/-] switch in fsi.

[KevinRansom]

The internal scenario with a 30 assembly limit is no longer an issue.

It defaults to on anyway.

[abonie]

We need to make sure disabling this option does not break anyone

Vlad says dotnet interactive was using it a year ago

[Szer]

It will definitely break a lot of stuff!
I'm using this option --multiemit- as a workaround for serializers who ignores CompilerGenerated
Please leave it in FSI 🙏

#13493
dotnet/machinelearning#6209

[goswinr]

I am also using --multiemit-, otherwise, I get a type load exception when hosting FSI in Rhino.

I have not been able to debug the type load exception yet. As a side effect of using --multiemit- i don't have line numbers on Exceptions.

[majocha]

It'd be a step in a right direction.
Let's just make sure the issues mentioned are addressed, and we do have tests for those use cases.