Support for bit manipulation tests

[adpaco-aws]

We have a couple of unssuported tests in:

rust-tests/cbmc-reg/BitManipulation/Unstable/fixme_main_fail.rs
rust-tests/cbmc-reg/BitManipulation/Stable/fixme_main_fail.rs

Note that some of them are related to count intrinsics, so #26 is related.

[adpaco-aws]

These tests were replaced by more complete tests in #880 and #883