SchemaImpl and CatalogImpl $replace() and $traverse() methods shouldn't recurse into Name or Comment parts

[lukaseder]

We're currently recursing into Name and Comment parts from within SchemaImpl and CatalogImpl methods $replace() and $traverse():

    @Override
    public final <R> R $traverse(Traverser<?, R> traverser) {
        return QOM.traverse(traverser, this, getQualifiedName());
    }

    @Override
    public final QueryPart $replace(Replacer replacer) {
        return QOM.replace(this, getQualifiedName(), getCommentPart(), CatalogImpl::new, replacer);
    }

This isn't being done in any other Named type, including TableImpl, TableFieldImpl, and many many others:

Let's remove this recursion for these reasons:

• Consistency
• Accidental effects (users not expecting this)
• Performance

[lukaseder]

Since there might be a (very unlikely) behavioural regression in a customer implementation of a Replacer call, I won't backport this change.