Infinite loop inside LSPMessageFormatter for some cases

[angelozerr]

In some case https://github.com/eclipse/lemminx/blob/875d5b427f9db918857df9db2b0939282b048a12/org.eclipse.lemminx/src/main/java/org/eclipse/lemminx/extensions/xerces/LSPMessageFormatter.java#L153 don't exit from the loop.

Given this XSD:

<?xml version="1.0" encoding="UTF-8"?>
<xs:schema
	xmlns:xs="http://www.w3.org/2001/XMLSchema"
	targetNamespace="http://foo">
	<xs:element name="foo">
		<xs:complexType>
			<xs:sequence>
				<xs:element name="bar" />
			</xs:sequence>
		</xs:complexType>
	</xs:element>
</xs:schema>

and this XML file:

<foo xmlns="http://foo" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://foo foo.xsd">
	<bar />
</foo>

error are crazy: