tree-optimization/103361 - fix unroll-and-jam direction vector handling

tree-optimization/103361 - fix unroll-and-jam direction vector handling

This properly uses lambda_int instead of truncating the direction
vector to int which leads to false unexpected negative values.

2021-11-23  Richard Biener  <rguenther@suse.de>

	PR tree-optimization/103361
	* gimple-loop-jam.c (adjust_unroll_factor): Use lambda_int
	for the dependence distance.
	* tree-data-ref.c (print_lambda_vector): Properly print a lambda_int.

	* g++.dg/torture/pr103361.C: New testcase.

(cherry picked from commit 6cd440670078af89d82cbb67e01a5ecec8eec238)