Ensure Groovy bean builder does not enforec XML validation

Since it is not parsing XML it makes no sense to be validating
and it would cause exceptions when importing "namespace"
features. This brings the Boot usage of the bean builder inline
with that in Spring Core.

Fixes gh-630

spring-boot/src/main/java/org/springframework/boot/BeanDefinitionLoader.java

@@ -81,7 +81,7 @@ class BeanDefinitionLoader {
 		this.annotatedReader = new AnnotatedBeanDefinitionReader(registry);
 		this.xmlReader = new XmlBeanDefinitionReader(registry);
 		if (isGroovyPresent()) {
-			this.groovyReader = new GroovyBeanDefinitionReader(this.xmlReader);
+			this.groovyReader = new GroovyBeanDefinitionReader(registry);
 		}
 		this.scanner = new ClassPathBeanDefinitionScanner(registry);
 		this.scanner.addExcludeFilter(new ClassExcludeFilter(sources));