value-relation: Small tweaks to tables

value-relation: Small tweaks to tables

As I said earlier, all these tables are used solely in value-relation.cc
and never modified, plus because VREL_LAST is small especially the
two-dimensional arrays are vast a lot of .data (or .rodata) space
- 576 bytes each.  The following patch makes those arrays static const
and uses unsigned char instead of relation_kind so that the
two-dimensional arrays shrink to 144 bytes.

2023-01-26  Jakub Jelinek  <jakub@redhat.com>

	* value-relation.cc (kind_string): Add const.
	(rr_negate_table, rr_swap_table, rr_intersect_table,
	rr_union_table, rr_transitive_table): Add static const, change
	element type from relation_kind to unsigned char.
	(relation_negate, relation_swap, relation_intersect, relation_union,
	relation_transitive): Cast rr_*_table element to relation_kind.
	(relation_to_code): Add static const.
	(relation_tests): Assert VREL_LAST is smaller than UCHAR_MAX.