Fix xml empty examples except first

[tienvx]

Issue: When using examples=3 for xml element, all xml elements (except the first element) doesn't have content.

Expected:

<?xml version='1.0'?>
<items>
	<item>
		<name>Item 1</name>
		<price>10</price>
	</item>
	<item>
		<name>Item 1</name>
		<price>10</price>
	</item>
	<item>
		<name>Item 1</name>
		<price>10</price>
	</item>Item list
</items>

Actual:

<?xml version='1.0'?>
<items>
	<item>
		<name>Item 1</name>
		<price>10</price>
	</item>
	<item>
		<name/>
		<price/>
	</item>
	<item>
		<name/>
		<price/>
	</item>Item list
</items>

This pull request:

• Add a missing test for defining xml element's content
• Fix this issue