Update function libraries to use iteration with Vectors

[rcaudy]

Once #3570 merges, we can and should change more or less all Vector iteration in our libraries to use iterator or stream methods, rather than looping on get calls. This is potentially far more efficient for some Vector types, especially those downstream of a groupBy, aggBy with Group, updateBy with RollingGroup, or rangeJoin with Group.

For example:

This code in Basic.ftl:

    static public <T> long countObj(ObjectVector<T> values) {
        if (values == null) {
            return NULL_LONG;
        }

        final long n = values.size();
        long count = 0;

        for (long i = 0; i < n; i++) {
            T c = values.get(i);

            if (!isNull(c)) {
                count++;
            }
        }

        return count;
    }

should be:

    static public <T> long countObj(ObjectVector<T> values) {
        if (values == null) {
            return NULL_LONG;
        }

        if (values.isEmpty()) {
            return 0;
        }

        long count = 0;
        for (final Iterator<T> vi = values.iterator(); vi.hasNext(); ){
            final T c = vi.next();

            if (!isNull(c)) {
                count++;
            }
        }

        return count;
    }

We could also write it like this, but it's probably worse:

    static public <T> long countObj(ObjectVector<T> values) {
        if (values == null) {
            return NULL_LONG;
        }

        if (values.isEmpty()) {
            return 0;
        }

        return values.iterator().stream().filter(c -> !isNull(c)).count();
    }

A related change we should also make: Avoid using Vector get when array access will do:

This code in Basic.ftl:

    static public <T> T[] replaceIfNull(ObjectVector<T> values, T replacement) {
        final int n = values.intSize("replaceIfNull");
        T[] result = values.toArray();

        for (int i = 0; i < n; i++) {
            result[i] = replaceIfNull(values.get(i), replacement);
        }

        return result;
    }

should be:

    static public <T> T[] replaceIfNull(ObjectVector<T> values, T replacement) {
        final int n = values.intSize("replaceIfNull");
        T[] result = values.toArray();

        for (int i = 0; i < n; i++) {
            result[i] = replaceIfNull(result[i], replacement);
        }

        return result;
    }

[rcaudy]

The pre-requisite PR has merged.

[rcaudy]

Loosely related to #3689