Add assignment operator to the TestBar test util class.
n.b. this change to test code introduces a lot of failures in the CUB unit tests. I'm not submitting those fixes -- I've done a few but not all of them.
This change will identify all places in CUB code that attempts an assignment to uninitialized memory. See https://github.com/NVlabs/cub/issues/184
Change:
I added a an assignment operator to the class, and I added a field named magic that I set to a certain value during construction. Only an object that has been constructed is likely to have that magic value properly set.
An assignment precondition is that the left-hand side is valid. The assignment operators I added assert that the magic member of the lhs has the correct value.
Converting to draft to prevent merging since this PR's purpose is to detect errors, not fix them.