Put old ES3 reserved words behind a flag

[pwnall]

Rhino currently chokes on this code that contains an ES3 reserved word.

options.long

Java keywords that aren't used in JavaScript are not reserved anymore, as of ES5:
http://ecma-international.org/ecma-262/5.1/#sec-7.6.1
https://developer.mozilla.org/en-US/docs/JavaScript/Reference/Reserved_Words

For this reason, I think that the JS tokenizer should only choke on ES3 reserved words when a flag is set. (or, even better, not at all)

The relevant code seems to be here:
https://github.com/mozilla/rhino/blob/master/src/org/mozilla/javascript/TokenStream.java#L135

Once that is fixed, the map below should probably be re-generated.
https://github.com/mozilla/rhino/blob/master/src/org/mozilla/javascript/TokenStream.java#L153

[harking]

This is also needed so Rhino does not die when running QUnit tests that use throws() test.

[krumpi]

It also make it impossible to do Ember.js precompilation in Rhino. Ember uses the volatile keyword which is ES3
See
emberjs/ember.js#957
emberjs/ember.js#1202

[Fordi]

This is a problem; it makes it impossible to unit test Ember applications using EnvJasmine.

[p-bakker]

Closing as this works now in Rhino, at least with Context.VERSION_ES6 as language level:

var obj = {};
obj.volatile = 123;
obj.long = 456