Scan types of yield expressions in classes too

Also, drop the other cases where they were ignored, since they're
forbidden in enums, and the others are fine wrt the comment that was
there.

Fixes #34892

src/compiler/utilities.ts

@@ -1221,11 +1221,8 @@ namespace ts {
                 case SyntaxKind.InterfaceDeclaration:
                 case SyntaxKind.ModuleDeclaration:
                 case SyntaxKind.TypeAliasDeclaration:
-                case SyntaxKind.ClassDeclaration:
-                case SyntaxKind.ClassExpression:
                     // These are not allowed inside a generator now, but eventually they may be allowed
-                    // as local types. Regardless, any yield statements contained within them should be
-                    // skipped in this traversal.
+                    // as local types. Regardless, skip them to avoid the work.
                     return;
                 default:
                     if (isFunctionLike(node)) {