Please review JDK-8057691: Nashorn: let & const declarations are not
shared between scripts:
http://cr.openjdk.java.net/~hannesw/8057691/
This implements global top-lexical scope as per the latest ES6 spec.
When running with --language=es6 this will add a switchpoint to
non-constant global scope properties that will be invalidated when a
script adds global lexical bindings. I've tested with Octane and there
are no performance regressions when running with --language=es6 compared
to default settings.
Hannes
