Make dart2js String.split match the VM version.

The dart2js version used the JS version of string split, which
includes captures between the parts. The Dart version doesn't do
that.

BUG= http://dartbug.com/21395
R=sgjesse@google.com

Review URL: https://codereview.chromium.org//677013002

git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge@41313 260f80e4-7a28-3924-810f-c04153c831b5
Fix typo reutrn -> return typo.

R=whesse@google.com

Review URL: https://codereview.chromium.org//684433003

git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge@41314 260f80e4-7a28-3924-810f-c04153c831b5
Fix type-errors.

R=whesse@google.com

Review URL: https://codereview.chromium.org//680073002

git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge@41315 260f80e4-7a28-3924-810f-c04153c831b5
Remove dead code from InvokeDartCode stub.

R=vegorov@google.com

Review URL: https://codereview.chromium.org//678993004

git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge@41316 260f80e4-7a28-3924-810f-c04153c831b5
Fix assertion not holding (calling with start==end) and typo.

Review URL: https://codereview.chromium.org//677423002

git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge@41317 260f80e4-7a28-3924-810f-c04153c831b5