Experiment: Use ALC in FSI sessions when on coreclr

[vzarytovskii]

Description

This is an attempt (timebox really) to improve #15669 by using unloadable ALC, if anyone wants to help testing it, it will be appreciated.

Fixes #15669

Checklist

• Test cases added

• Performance benchmarks added in case of performance changes

• Release notes entry updated:

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  • Correctly handle assembly imports with public key token of 0 length. (Issue #16359, PR #16363)
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[github-actions]

❗ Release notes required

@vzarytovskii,

Caution

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Change path	Release notes path	Description
src/Compiler	docs/release-notes/.FSharp.Compiler.Service/8.0.300.md	No release notes found or release notes format is not correct

[vzarytovskii]

It's failing to load FSI-ASSEMBLY now. It will need more work and debugging. I may come back to it in the future, or anyone else is free to investigate.

[vzarytovskii]

That didn't work out, not gonna delete branch if anyone will want to pick it up.

[majocha]

IIUC conditional compilation is out of question here? I'm thinking trying an unloadable sub AppDomain for legacy version and an ALC for core, but with netstandard2.0 it seems neither are supported.