Add missing properties to xsl stub (#12334)

* Define doXInclude for XSLTProcessor, and test the property

This was added in 8d1427dd98, but never defined on the stub.
It was more

Add missing properties to xsl stub (#12334)

* Define doXInclude for XSLTProcessor, and test the property

This was added in 8d1427dd98, but never defined on the stub.
It was more or less fine when dynamic properties were not deprecated,
but now they throw a deprecation warning. To fix it, define on the stub.
This should also help discoverability of the functionality.

* Define cloneDocument for XSLTProcessor, and test the property

This was introduced in 5c039bbad9, but never defined on the stub.
It was more or less fine when dynamic properties were not deprecated,
but now they throw a deprecation warning. To fix it, define on the stub.
This should also help discoverability of the functionality.

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