[localfix] FormItem doesnt position controls correctly

Steps to reproduce:
1. Compile and run attached MXML example.

Actual Results:
A couple of the FormItem labels don't match (notably ONe and THREe).
The first label and CheckBox box don't align (the box is a few pixels too high – or the label is too low).
The third label and CheckBox box don't align either (the label is WAAAAAAY too high).

Expected Results:
The CheckBox boxes and labels should be aligned correctly.

Workaround (if any):
a) Don't use an empty CheckBox label.
b) For a Halo CheckBox in Spark application, you can set the label to a single space.
c) For a Spark CheckBox in a Spark application, you can NOT set the label to a single space, but you can type a character and then set the textAlpha property to 0 to make the label disappear.

<?xml version="1.0" encoding="utf-8"?>
<s:Application xmlns:fx="http://ns.adobe.com/mxml/2009"
xmlns:s="library://ns.adobe.com/flex/spark"
xmlns:mx="library://ns.adobe.com/flex/halo"
creationComplete="init();">

<mx:Form>
<mx:FormItem label="Spark:" backgroundColor="red">
<s:CheckBox label="." textAlpha="0" />
</mx:FormItem>
<mx:FormItem label="Spark (with):" backgroundColor="red">
<s:CheckBox label="label" />
</mx:FormItem>
<mx:FormItem label="Halo:" backgroundColor="red">
<mx:CheckBox label=" " />
</mx:FormItem>
<mx:FormItem label="Halo (with):" backgroundColor="red">
<mx:CheckBox label="label" />
</mx:FormItem>
<mx:FormHeading creationComplete="event.currentTarget.label = mx_internal::VERSION;" />
</mx:Form>

</s:Application>