[whatwg] Workers and URL origin check

[Kristof Zelechovski]

I was wrong: CONST values and conditional compilation variables land as
properties of the window, which means they are unavailable to other scripts
only if the defining script is external and deferred.
Still, I do not think this behavior is mandatory for run-time; there may be
symbols that are handled by the parser and do not survive after the script
has been loaded.  Admittedly, neither JavaScript nor Basic support such a
construct, but it would be easy to think of a scripting language that does.
Hypothetically,
Chris