(And any PECLs returning `zend_empty_array` in the handler->get_properties
overrides)
Closes GH-9697
This is similar to the fix used in d9651a9419
for array_walk.
This should make it safer for php-src (and PECLs, long-term) to return
the empty immutable array in `handler->get_properties` to avoid wasting memory.
See https://github.com/php/php-src/issues/9697#issuecomment-1273613175
The only possible internal iterator position for the empty array is at the end
of the empty array (nInternalPointer=0).
The `zend_hash*del*` helpers will always set nInternalPointer to 0 when an
array becomes empty,
regardless of previous insertions/deletions/updates to the array.
