tree-optimization/105226 - avoid splitting abnormal edges

tree-optimization/105226 - avoid splitting abnormal edges

Vectorizer loop versioning tries to version outer loops if possible
but fails to check whether it can actually split the single exit
edge as it will do.

2022-04-12  Richard Biener  <rguenther@suse.de>

	PR tree-optimization/105226
	* tree-vect-loop-manip.c (vect_loop_versioning): Verify
	we can split the exit of an outer loop we choose to version.

	* gcc.dg/pr105226.c: New testcase.

(cherry picked from commit 62d5bb0f35fb6ec373eaac942755585a633528a0)