Problem
Although tests can be parameterized using the block_size param, this param is not "respected" in the sense that even if a test is parameterized as follows:

let params = TestParams {
    ...
    block_size: ByteSize::kib(50),
    ...
}

the actual block size is always set to be a u64 (the factorized value) and the commit certificate and hence the actual block size is not associated with the set block_size.
The root cause of the above issue is that block_size is not used anywhere to populate the value with data by using the extensions field.