tree-optimization/119096 - bogus conditional reduction vectorization

When we vectorize a .COND_ADD reduction and apply the single-use-def
cycle optimization we can end up chosing the wrong else value for
subsequent .COND_ADD.  The following rectifies this.

	PR tree-optimization/119096
	* tree-vect-loop.cc (vect_transform_reduction): Use the
	correct else value for .COND_fn.

	* gcc.dg/vect/pr119096.c: New testcase.