Add test for checking Haskell/Python opcode equivalence

This is a very big hack for testing the equivalence of Python and
Haskell opcode definitions. See the docstring for details; I'm not
very happy with the solution but it does the job.

An alternate option would be to launch the Python code when
initialising the tests, pass (somehow) the resource through all of the
test suite to this function, and then use normal QuickCheck
properties. Or maybe we find a better solution later; for now, this
does the job.

Signed-off-by: Iustin Pop <iustin@google.com>
Reviewed-by: Agata Murawska <agatamurawska@google.com>