Move return value of rb_define_finalizer out

Moves return value logic of rb_define_finalizer out from
rb_gc_impl_define_finalizer.

gc.c

@@ -1560,7 +1560,12 @@ rb_define_finalizer(VALUE obj, VALUE block)
 {
     should_be_finalizable(obj);
     should_be_callable(block);
-    return rb_gc_impl_define_finalizer(rb_gc_get_objspace(), obj, block);
+
+    block = rb_gc_impl_define_finalizer(rb_gc_get_objspace(), obj, block);
+
+    block = rb_ary_new3(2, INT2FIX(0), block);
+    OBJ_FREEZE(block);
+    return block;
 }
 
 void

gc/default.c

@@ -2983,8 +2983,7 @@ rb_gc_impl_define_finalizer(void *objspace_ptr, VALUE obj, VALUE block)
             for (i = 0; i < len; i++) {
                 VALUE recv = RARRAY_AREF(table, i);
                 if (rb_equal(recv, block)) {
-                    block = recv;
+                    return recv;
-                    goto end;
                 }
             }
         }
@@ -2996,9 +2995,7 @@ rb_gc_impl_define_finalizer(void *objspace_ptr, VALUE obj, VALUE block)
         rb_obj_hide(table);
         st_add_direct(finalizer_table, obj, table);
     }
-  end:
+
-    block = rb_ary_new3(2, INT2FIX(0), block);
-    OBJ_FREEZE(block);
     return block;
 }