Complete the Test opcodes

This adds the OpTestAllocator, OpTestJqueue and OpTestDummy
opcodes. The OpTestAllocator seems to need some cleanup (on the Python
side), for now we implement it as is. As for the other two, while not
used in production, we should have full coverage for them as well.

Signed-off-by: Iustin Pop <iustin@google.com>
Reviewed-by: Helga Velroyen <helgav@google.com>