Lower for loops before lowering cond in genmatch

While converting some fold_cond_expr_with_comparison
to match, I found that I wanted to use "for cnd (cond vec_cond)"
but that was not causing the lowering of cond to happen.
What was happening was the lowering of the for loop
was happening after the lowering of the cond. So
swapping was the correct thing to do but it also
means we need to copy for_subst_vec in lower_cond.

OK?  Bootstrapped and tested on x86_64-linux-gnu with no regressions.

gcc/ChangeLog:

	* genmatch.c (lower_cond): Copy for_subst_vec
	for the simplify also.
	(lower): Swap the order for lower_for and lower_cond.