lazily computed range of all suffixes of stringA that are a prefix of stringB.
auto matches = suffixPrefixMatches("abcdef", "cdefghij"); assert(equal(matches, ["cdef"]));
auto matches = suffixPrefixMatches("abcdefcdef", "cdefcdefghij"); assert(equal(matches, ["cdefcdef", "cdef"]));
Find all suffixes of stringA that are a prefix of stringB. The matches are computed lazily, decreasing length of the match.