process.c (waitpid_cleanup): unconditionally remove from waiters

This is the safer option, as there seems to be cases where checking
waitpid_state.ret is insufficient in ensure.  I'm not 100% sure
why this is, but this change was required for my work-in-progress
Thread::Light patch series, too...

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@64782 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

process.c

@@ -1106,7 +1106,11 @@ waitpid_cleanup(VALUE x)
 {
     struct waitpid_state *w = (struct waitpid_state *)x;
 
-    if (w->ret == 0) {
+    /*
+     * XXX w->ret is sometimes set but list_del is still needed, here,
+     * Not sure why, so we unconditionally do list_del here:
+     */
+    if (TRUE || w->ret == 0) {
         rb_vm_t *vm = rb_ec_vm_ptr(w->ec);
 
         rb_native_mutex_lock(&vm->waitpid_lock);