Copy irregexp related code from V8.

This "syntactic" change copies the irregexp code from V8 r24065 to Dart.
Compared to the V8 files the only changes are that the files have been
suitably renamed, headers and footers have been updated, and most of the
unneeded code has been replaced by a 'SNIP' marker. None of the files
are added to the build and they cannot compile. Integration with the
Dart VM is done in a follow-up CL [1].

[1]: https://codereview.chromium.org/683433003/

BUG=
R=iposva@google.com

Review URL: https://codereview.chromium.org//678193004

git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge@41455 260f80e4-7a28-3924-810f-c04153c831b5