When we're (int|num)ifying a list or hash...

re-write into an nqp::elems(). Spesh can do this too, but if we can do
it earlier, why not do so.

src/NQP/Optimizer.nqp

@@ -293,6 +293,7 @@ class NQP::Optimizer {
             if nqp::istype($op[0], QAST::Var) {
                 my $sigil := nqp::substr($op[0].name, 0, 1);
                 if $sigil eq '@' || $sigil eq '%' {
+                    $op.op('elems');
                     $op.returns(int)
                 }
             }