fix(android): scrolling a ListView with headerView

[m1ga]

JIRA: https://jira.appcelerator.org/browse/AC-6670

Provide a clear PR title prefixed with [TICKET]

Optional Description:

If the first element of a ListView is not a section but a headerView it will crash with the current SDK 9.3.1 while scrolling.

Example:

var win = Ti.UI.createWindow({ backgroundColor: 'white' });
var headerView = Ti.UI.createView({ height: Ti.UI.SIZE, width: Ti.UI.FILL, backgroundColor:"#444"});
var headerLabel = Ti.UI.createLabel({ height:Ti.UI.SIZE, width: Ti.UI.FILL, left: '15dp', right: '15dp', top: '15dp', color: 'black', text: 'Demo text'});
headerView.add(headerLabel);
var listView = Ti.UI.createListView({height: Ti.UI.FILL,top: 0,headerView: headerView});
var sections = [];
var fruitDataSet = [
    { properties: { title: 'Apple', color: 'black' } },
    { properties: { title: 'Banana', color: 'black' } },
];
var fruitSection = Ti.UI.createListSection({ headerTitle: 'Fruits', items: fruitDataSet });
sections.push(fruitSection);
var vegDataSet = [
    { properties: { title: 'Carrots', color: 'black' } },
    { properties: { title: 'Potatoes', color: 'black' } },
];
var vegSection = Ti.UI.createListSection({ headerTitle: 'Vegetables', items: vegDataSet });
sections.push(vegSection);
var fishDataSet = [
    { properties: { title: 'Cod', color: 'black' } },
    { properties: { title: 'Haddock', color: 'black' } },
    { properties: { title: 'Haddock', color: 'black' } },
    { properties: { title: 'Haddock', color: 'black' } },
    { properties: { title: 'Haddock', color: 'black' } },
    { properties: { title: 'Haddock', color: 'black' } },
    { properties: { title: 'Haddock', color: 'black' } },
    { properties: { title: 'Haddock', color: 'black' } },
    { properties: { title: 'Haddock', color: 'black' } },
    { properties: { title: 'Haddock', color: 'black' } },
    { properties: { title: 'Haddock', color: 'black' } },
    { properties: { title: 'Haddock', color: 'black' } },
    { properties: { title: 'Haddock', color: 'black' } },
    { properties: { title: 'Haddock', color: 'black' } },
    { properties: { title: 'Haddock', color: 'black' } },
    { properties: { title: 'Haddock', color: 'black' } },
    { properties: { title: 'Haddock', color: 'black' } },
    { properties: { title: 'Haddock', color: 'black' } },
    { properties: { title: 'Haddock', color: 'black' } },
    { properties: { title: 'Haddock', color: 'black' } },
    { properties: { title: 'Haddock', color: 'black' } },
    { properties: { title: 'Haddock', color: 'black' } },
    { properties: { title: 'Haddock', color: 'black' } },
    { properties: { title: 'Haddock', color: 'black' } },
    { properties: { title: 'Haddock', color: 'black' } },
    { properties: { title: 'Haddock', color: 'black' } },
    { properties: { title: 'Haddock', color: 'black' } },
    { properties: { title: 'Haddock', color: 'black' } },
    { properties: { title: 'Haddock', color: 'black' } },
    { properties: { title: 'Haddock', color: 'black' } },
    { properties: { title: 'Haddock', color: 'black' } },
];
var fishSection = Ti.UI.createListSection({ headerTitle: 'Fish', items: fishDataSet });
sections.push(fishSection);
listView.sections = sections;
listView.addEventListener("scrollend",function(e){console.log(e.firstVisibleItemIndex)});
win.add(listView);
win.open();

[build]

	Fails
🚫	🔬 There are library changes, but no changes to the unit tests. That's OK as long as you're refactoring existing code, but will require an admin to merge this PR. Please see README.md#unit-tests for docs on unit testing.
🚫	Tests have failed, see below for more information.

	Messages
📖	💾 Here's the generated SDK zipfile.
📖	🎉 Another contribution from our awesome community member, m1ga! Thanks again for helping us make Titanium SDK better. 👍
📖	✊ The commits in this PR match our conventions! Feel free to Rebase and Merge this PR when ready.
📖	❌ 1 tests have failed There are 1 tests failing and 899 skipped out of 14875 total tests.

Tests:

Classname	Name	Time	Error
ios.macos.Titanium.Blob	image dimensions should be reported in pixels (10.15.5)	0.005	Error: expected 6 to be 11 value@file:///node_modules/should/cjs/should.js:356:23 postlayout@file:///ti.blob.test.js:483:33

Generated by 🚫 dangerJS against 1396065

[garymathews]

Superseded by #12424