IDEA-121961 Debugger: evaluate from variables doesn't include context
store vfs charset in user data

* it used to give memory usage advantages on 64-bit systems and was free due to
object size alignment by 8
* now this field is mostly null and it's not free anymore,  due to changed field count
platform: let out/err readers have independent policies
EA-56596 - CCE: XmlLanguageInjector$.visitElement