v62.0.4

Give the legacy enumeration bridges bodies and emit them once (#2879)

Bugs fixed:

• The synthesized IEnumerable.GetEnumerator and IEnumerator.Current
  returned null, so no ghul type could be enumerated through the legacy
  interfaces
• A class inheriting the implementation from its base re-emitted the
  bridge and an override row for an interface it does not declare, which
  ILLink rejects

Technical:

• A bridge forwards to the generic member, virtually on a class so an
  override is reached, directly on a struct, boxing a value-type or
  type-parameter current
• A generator frame has no symbols for its members, so the walk records
  its own GetEnumerator and get_Current handles as it writes them

Co-authored-by: ghul-coder[bot] <286450068+ghul-coder[bot]@users.noreply.github.com>
Co-authored-by: Claude Opus 5 noreply@anthropic.com