[TIMOB-8716] Android: When switching between tabs, keyboard stays on screen

The problem

Let's say that there is a text field in one tab that is focused so that keyboard is showed on the screen. Switching to other tab does not hide keyboard, despite the fact that the tab that we're switching on does not have text field in it.

Steps to reproduce

To see this issue, run this example:

var tabGroup = Ti.UI.createTabGroup();

var tab1 = Ti.UI.createTab({
    title: 'Tab 1',
    window: Ti.UI.createWindow()
});

var tab2 = Ti.UI.createTab({
    title: 'Tab 2',
    window: Ti.UI.createWindow()
});

var textField = Ti.UI.createTextField({
    width: 300,
    height: 50,
	keyboardType : Ti.UI.KEYBOARD_NUMBER_PAD
});

tab1.window.add(textField);

tabGroup.addTab(tab1);
tabGroup.addTab(tab2);

tabGroup.open();

Text field in first tab should be autofocused, if it's not, click on it. When keyboard is shown on the screen, click on "Tab 2". You should see that keyboard is still up and it has changed its type from numeric to alphanumeric.

Expected behavior

When tab is switched, keyboard should be hidden.