`ByteQuadsCanonicalizer.addName(String, int, int)` has incorrect handling for case of `q2 == null`

[cowtowncoder]

Up to Jackson 2.12.2, SymbolTable has:

    public String addName(String name, int q1, int q2) {
        _verifySharing();
        if (_intern) {
            name = InternCache.instance.intern(name);
        }
        int hash = (q2 == 0) ? calcHash(q1) : calcHash(q1, q2);
        ...
}

in which special handling is used if second "quad" is all zeroes. Presumable at some point calls were expected to be made with just q1 defined, q2 empty; and assumption probably being that this should for some reason also be supported just as an alias.

But it seems that doing this can be problematic if names (ids) with zero bytes are allowed: whether they are or not is debatable, but binary format like CBOR and Smile can technically encode such sequences. If so, there's a mismatch between "findName()" and "addName()" methods.

There also does not seem to be any good reason to have this check; plus removing it is a (small, granted) performance improvement.

So let's remove it from 2.13.0.