the tests for bit vectors, sparse vectors, and mixed now share the same test code.
the tests for bit vectors, sparse vectors, and mixed now share the same test code.

Added a missing test case (sparse test was omitted for one test) and added cross-tests the other way

bp-kelley/rdkit,adalke/rdkit,greglandrum/rdkit,jandom/rdkit,rvianello/rdkit,rdkit/rdkit,greglandrum/rdkit,jandom/rdkit,jandom/rdkit,ptosco/rdkit,rvianello/rdkit,bp-kelley/rdkit,adalke/rdkit,bp-kelley/rdkit,greglandrum/rdkit,greglandrum/rdkit,rdkit/rdkit,rdkit/rdkit,jandom/rdkit,adalke/rdkit,jandom/rdkit,ptosco/rdkit,rvianello/rdkit,adalke/rdkit,bp-kelley/rdkit,rdkit/rdkit,ptosco/rdkit,greglandrum/rdkit,jandom/rdkit,greglandrum/rdkit,greglandrum/rdkit,ptosco/rdkit,rvianello/rdkit,rdkit/rdkit,adalke/rdkit,adalke/rdkit,bp-kelley/rdkit,greglandrum/rdkit,adalke/rdkit,rdkit/rdkit,ptosco/rdkit,rdkit/rdkit,ptosco/rdkit,rvianello/rdkit,rdkit/rdkit,ptosco/rdkit,rvianello/rdkit,bp-kelley/rdkit,bp-kelley/rdkit,bp-kelley/rdkit,jandom/rdkit,rvianello/rdkit,jandom/rdkit,adalke/rdkit,ptosco/rdkit,rvianello/rdkit