tree-optimization/114792 - order loops to unloops in CH

When we use unloop_loops we have to make sure to have loops ordered
inner to outer as otherwise we can wreck inner loop structure where
unlooping relies on that being intact.  The following re-sorts the
vector of to unloop loops after copy-header as that adds to the
vector in two places and the wrong order.

	PR tree-optimization/114792
	* tree-ssa-loop-ch.cc (ch_order_loops): New function.
	(ch_base::copy_headers): Sort loops to unloop inner-to-outer.

	* gcc.dg/torture/pr114792.c: New testcase.