Implement Array.forEach on browsers that do not provide it for ES53's internal use.

ES53 uses forEach internally distinct from the version it exposes to cajoled code.  This CL
provides a version .forEach for browsers that do not provide it.

See http://code.google.com/p/google-caja/issues/detail?id=1328

@4402

[Jasvir, 2011-03-21 15:45:54]

ping

[metaweta, 2011-03-21 20:56:59]

http://codereview.appspot.com/4274066/diff/1/src/com/google/caja/es53.js
File src/com/google/caja/es53.js (right):

http://codereview.appspot.com/4274066/diff/1/src/com/google/caja/es53.js#newc...
src/com/google/caja/es53.js:185: // Missing on IE
Since we're now creating this on platforms that don't have it built in, the
existing whitelisting doesn't need "createOrWrap", since there's never a need to
create it, so please update that as well.

[Jasvir, 2011-03-22 20:58:24]

snapshot

[metaweta, 2011-03-22 22:00:37]

lgtm