TypeDescriptor throws NPE due to because AnnotatedElement proxy is not cloning arrays

[philwebb]

Similar to #22655, the TypeDescriptor.AnnotatedElementAdapter class does not defensively clone the returned array. This means that second calls can result in the following NPE:

Caused by: java.lang.NullPointerException
	at org.springframework.core.convert.TypeDescriptor.annotationEquals(TypeDescriptor.java:502)
	at org.springframework.core.convert.TypeDescriptor.annotationsMatch(TypeDescriptor.java:492)
	at org.springframework.core.convert.TypeDescriptor.equals(TypeDescriptor.java:466)
	at org.springframework.core.convert.support.GenericConversionService$ConverterCacheKey.equals(GenericConversionService.java:470)
	at org.springframework.util.ObjectUtils.nullSafeEquals(ObjectUtils.java:325)
	at org.springframework.util.ConcurrentReferenceHashMap$Segment.findInChain(ConcurrentReferenceHashMap.java:648)
	at org.springframework.util.ConcurrentReferenceHashMap$Segment.getReference(ConcurrentReferenceHashMap.java:504)
	at org.springframework.util.ConcurrentReferenceHashMap.getReference(ConcurrentReferenceHashMap.java:265)
	at org.springframework.util.ConcurrentReferenceHashMap.get(ConcurrentReferenceHashMap.java:235)
	at org.springframework.core.convert.support.GenericConversionService.getConverter(GenericConversionService.java:255)
	at org.springframework.core.convert.support.GenericConversionService.canConvert(GenericConversionService.java:145)
	at org.springframework.boot.context.properties.bind.BindConverter$TypeConverterConversionService.canConvert(BindConverter.java:211)
	at org.springframework.boot.context.properties.bind.BindConverter$CompositeConversionService.convert(BindConverter.java:170)
	at org.springframework.boot.context.properties.bind.BindConverter.convert(BindConverter.java:98)
	at org.springframework.boot.context.properties.bind.BindConverter.convert(BindConverter.java:90)
	at org.springframework.boot.context.properties.bind.Binder.handleBindResult(Binder.java:234)
	at org.springframework.boot.context.properties.bind.Binder.bind(Binder.java:223)

The arrays is also returned from the public getAnnotations() and getDeclaredAnnotations() methods.