Use checkeq instead of creating a boolean expr when using check()

The test suite use a lot of:

check(last_status == cb::mcbp::Status::Success, "failed to blah blah"); 

If the test fails the error message is the non-informative:

Test failed: `failed to blah blah' (last_status == cb::mcbp::Status::Success)

Instead the code should be using checkeq which is called like:

checkeq(cb::mcbp::Status::Success, last_status.load(), "failed to blah blah"); 

This would print out the actual value of last status when the tests fail so that we can figure what went wrong.