Add workaround for XmlSchema serialization.
Add workaround for XmlSchema serialization.

Somewhere in System.Xml requires NameTable to be canonically reused when
deserializing XmlSchema, so that certain deserialization part can check
only reference equality.

Since we have hybrid System.Xml implementation for XmlSerializer, this
is not completely achieved and with reference comparison it causes some
schema deserialization failure. To avoid this problem, just disable
reference comparison. It should not affect outside XmlSchema serialization.

directhex/referencesource,ludovic-henry/referencesource,evincarofautumn/referencesource,stormleoxia/referencesource,mono/referencesource,esdrubal/referencesource