tree-vect-data-refs.c (vect_mark_for_runtime_alias_test): Factor out code checking if runtime alias check is possible to below ...

	* tree-vect-data-refs.c (vect_mark_for_runtime_alias_test): Factor
	out code checking if runtime alias check is possible to below ...
	Call the new function.
	* tree-data-ref.c (runtime_alias_check_p): ... to new function.
	* tree-data-ref.h (runtime_alias_check_p): New decalaration.

From-SVN: r248962