sl/check-property.sh: stop using the deprecated 'p_' prefix

... in p_valid-free, p_valid-deref, and p_valid-memtrack
sl/adt_op_match: fix a copy-paste mistake in seekTemplateMatchInstances()

... introduced in commit 8aff344566276530aabac041eca2bf1769e744ae.
sl/adt_op_match: fix computation of ID mapping from templates