helper: action and tag regexps always match the same string

If an action has characters that are special in regular expressions,
like "iFoo(hello)" has parenthesis, action-regexp "iFoo(hello)" did
not match to that action. This is fixed by first comparing equality of
these strings, and only in case of difference, doing regular
expression match. This affects many coverages and heuristics (include,
exclude, weight, etc.) where action-regexps and tag-regexps are used.