[whatwg] [JavaScript / Web ECMAScript] Dropping the “escaped reserved words” compatibility requirement

[Mathias Bynens]

Following the discussion in #whatwg and on
https://bugzilla.mozilla.org/show_bug.cgi?id=744784 and
https://bugs.ecmascript.org/show_bug.cgi?id=277, I’ve filed the
following bugs asking to remove this non-standard extension as there
don’t seem to be any strong compatibility requirements:

* Opera/Carakan: https://bugs.opera.com/browse/DSK-369398
* Chrome/V8: http://code.google.com/p/v8/issues/detail?id=2222
* Safari/JavaScriptCore: https://bugs.webkit.org/show_bug.cgi?id=90678