Fix type loader not recognizing overridden method (#56337)

Fix type loader not recognizing overridden method (#56337)

* Fix type loader not recognizing overridden method
- Result of a bad change when removing support for full stub dispatch in .NET 4.0 timeframe (circa 2008)
- Caused issue when the following set of conditions were all true
  - The type implements an interface
  - The interface has more virtual methods on it than the number of virtual methods on the base type of the type.
  - The base type implements the interface partially (and the partial implementation has a slot number greater than the number of virtual methods on the base type + its base types)
  - The type does not re-implement the interface methods implemented by the base type.
- The comment referred to situations where stub dispatch was used to resolve non-virtual calls which is a very long time removed feature and is not applicable to today's codebase.
- Not reachable with versions of C# that shipped before the default interfaces feature, but with that feature became easily reachable. Has been a bug since .NET 4 for handwritten IL.

Fixes #44533