check that all loops are valid in the combined region

check that all loops are valid in the combined region

the bug was exposed by rewriting an if condition into an assert in the computation
of the loop iteration domains.

	* graphite-scop-detection.c (loop_is_valid_scop): Renamed loop_is_valid_in_scop.
	(scop_detection::harmful_stmt_in_region): Renamed harmful_loop_in_region.
	Call loop_is_valid_in_scop.

Co-Authored-By: Sebastian Pop <s.pop@samsung.com>
From-SVN: r232653