faster domain_contains/2, creating less garbage
faster domain_contains/2, creating less garbage

This is especially noticeable in CSPs with tuples_in/2 constraints,
which make extensive use of domain_contains/2.

edechter/swipl-devel,koryonik/swipl-devel,mndrix/swipl-devel,mndrix/swipl-devel,mndrix/swipl-devel,koryonik/swipl-devel,edechter/swipl-devel,mndrix/swipl-devel,mndrix/swipl-devel,jn7163/swipl-devel,jn7163/swipl-devel,jn7163/swipl-devel,jn7163/swipl-devel,jn7163/swipl-devel,koryonik/swipl-devel,koryonik/swipl-devel,koryonik/swipl-devel,edechter/swipl-devel,edechter/swipl-devel,edechter/swipl-devel