Remove tinytest casts that were suppressing them. Fix for #11825.
This brings us to tinytest commit 709a36ba63ff16d8. The only big change tor-side is that we don't need our own test_mem_op operation any longer.
Now a NULL argument to either makes it fail, not crash. Fies bug 9004; bugfix on 0.2.2.4-alpha.
The rationale for treating these files differently is that we should be checking upstream for changes as applicable, and merging changes upstream as warranted.