CI: Add spark expression coverage to build process

[comphead]

          Would you mind to upload the coverage result as an artifact so that every CI run could produce a test report?

The related part is at 56ccf6a#diff-02adba3bf9683d1c5c48e061e0108e79aea4f6d9cfbafebfd935fd3470fb7140R64

Originally posted by @advancedxy in #263 (comment)