* Add test for emptying autorelease pool
* Fix arc autorelease pool emptying when adding further references
When releasing a reference in the arc autorelease pool, it is
possible and anticipated that new references may added to the pool.
This fix addresses an edge case where releasing a reference in the
same pool page as the stop position can add more references which
cause the insertion of a new page and emptyPool() returns early
after emptying the new page.
Graham--M