[TIMOB-15889] (3_2_X) iOS: Clear out listItem when cell deallocates

Backport of PR #5358
Fixes following tickets
[TIMOB-15889](https://jira.appcelerator.org/browse/TIMOB-15889)
[TIMOB-15885](https://jira.appcelerator.org/browse/TIMOB-15885)

Regression

KS->Views->ListView