fix(listview) segmentedbar crash

[Codex-]

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• There is an issue for the bug/feature this PR is for. To avoid wasting your time, it's best to open a suggestion issue first and wait for approval before working on it.
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• All existing tests are passing: https://github.com/NativeScript/nativescript-angular/blob/master/DevelopmentWorkflow.md#running-the-tests
• Tests for the changes are included.

I ran the appium tests but it couldn't hurt to double check these too. In addition to this, I have also provided a test in the test-app-ng application.

Manually tested on both iOS and Android.

What is the current behavior?

In a class with a member that contains an array of SegmentedBarItems, using this to populate a SegmentedBar in a listView.

When the listView has scrolled below the view of the SegmentedBar and the items driving the listView change, scrolling back to the SegmentedBar causes a hard crash on Android.

What is the new behavior?

Introduce a simple check as to whether a new value on setPropertyInternal is an array, if so, check and unreference any of the items references to a parent & parentNode.

The demo page contains a simple list containing a SegmentedBar as an item, scrolling to the bottom of the list reveals a button that triggers the effect being fixed here. Press this and the list will change, then attempt to scroll to the top of the list.

Fixes #900

[Codex-]

Not sure who to tag for getting a reviewer for this PR, @vakrilov perhaps?

[Codex-]

Sorry to bump, has been a few months now and resolves an open issue.

Is it possible to have someone review this please? @NickIliev

[NathanWalker]

Hi @Codex- thank for this PR - I was able to merge latest master in here (which includes angular 9 support) and would like to get this published by Thursday, thanks for the effort here 👍

[Codex-]

Awesome, thanks for that @NathanWalker

Would it be possible to add it as a hotfix release to the existing stable version too? I understand if not!

[NathanWalker]

Definitely - this will go out with 9.0.1 or 9.0.2 this week 🤗