Send bytea in the correct format in all cases

I failed to spot this case in 6a22d6803c4697d6177a54c379f8d3de56,
which means that we don't have automated tests for that case.  Add
them as well.
Revert "Test Queryer as well as Execer"

Queryer wasn't present in Go 1.0, so we can't try to run this test
there, at least not as written.  Reverting for now.

This reverts commit de28fd30151bcc4bc7833c82d59051c443cee3aa.