tree-optimization/111846 - put simd-clone-info into SLP tree

tree-optimization/111846 - put simd-clone-info into SLP tree

The following avoids bogously re-using the simd-clone-info we
currently hang off stmt_info from two different SLP contexts where
a different number of lanes should have chosen a different best
simdclone.

	PR tree-optimization/111846
	* tree-vectorizer.h (_slp_tree::simd_clone_info): Add.
	(SLP_TREE_SIMD_CLONE_INFO): New.
	* tree-vect-slp.cc (_slp_tree::_slp_tree): Initialize
	SLP_TREE_SIMD_CLONE_INFO.
	(_slp_tree::~_slp_tree): Release it.
	* tree-vect-stmts.cc (vectorizable_simd_clone_call): Use
	SLP_TREE_SIMD_CLONE_INFO or STMT_VINFO_SIMD_CLONE_INFO
	dependent on if we're doing SLP.

	* gcc.dg/vect/pr111846.c: New testcase.