Re-enable realsig

[KevinRansom]

Realsig got disabled by a merge back from release/dev10.

The recent merge of the Equals() optimization identified an issue with DU codegen. There was an issue with how DU code generation worked for DU type members for realsig-. It always generates members with the scope of the DU case. The Equals() optimization applied to a public DU with internal cases was generated with an internal scope rather than public visibility.

This change:

1. Ensures that Equals is produced with the scope of the DU rather than the scope of the case.
2. Updates surface area baseline to include corrected DUs
3. Adds regression tests that verify codegen and visibility for realsig+ and realsig-

[github-actions]

⚠️ Release notes required, but author opted out

Warning

Author opted out of release notes, check is disabled for this pull request.
cc @dotnet/fsharp-team-msft

[KevinRansom]

//cc @psfinaki @vzarytovskii @T-Gro

This is ready

[psfinaki]

Do I get it right that the surface area is now the same with both realsig on and off?

If so, this hack should be removed.

[KevinRansom]

Do I get it right that the surface area is now the same with both realsig on and off?

If so, this hack should be removed.

Removed

[psfinaki]

Thanks Kevin for handling this.