Support for arbitrary self-referential static fields on a type

[davidwrighton]

• Instead of loading the static field type, use metadata directly to pull the needed info if we can't load the target type.
• Add tests covering various scenarios found by customers in the last year or so
• Remove existing scheme which could handle directly self referential statics
• Defer checking RVA static valuetypes for their field type until a later type loader stage
  • Add VMFLAG for HasRVAStaticFields
• Remove VMFLAG for HasPublicFields, this was found to be unused (its a legacy of an old CAS type loader check which no longer exists)

Fixes #104511

[Copilot]

Pull Request Overview

This PR adds support for arbitrary self-referential static fields on types by improving type loading and validation mechanisms. Instead of relying on loading the static field type, it uses metadata directly to extract needed information when the target type cannot be loaded, preventing circular dependency issues.

Key changes:

• Replaces the existing self-referential static field handling scheme with a more robust metadata-based approach
• Defers RVA static valuetype field validation to a later type loader stage to avoid circular dependencies
• Removes the unused HasPublicFields VM flag and replaces it with HasRVAStaticFields

Reviewed Changes

Copilot reviewed 6 out of 6 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
SelfReferentialStatics.csproj	New test project configuration with unsafe blocks enabled
SelfReferentialStatics.cs	Comprehensive test cases covering various self-referential static field scenarios
methodtablebuilder.h	Removes HasNonPublicFields methods and adds GetCorElementTypeOfTypeDefOrRefForStaticField declaration
methodtablebuilder.cpp	Core implementation replacing old self-ref handling with metadata-based approach
class.h	Renames VMFLAG_HASNONPUBLICFIELDS to VMFLAG_HASRVASTATICFIELDS and related methods
class.cpp	Adds deferred validation for RVA static fields during LoadExactParents

[kg]

So much deleted code 🥳
LGTM aside from comments