EmitCreateIteratorResult loads map from function's context

Caching or serialization can cause full-codegen output to be shared
between contexts.  CreateIteratorResult, however, was doing the wrong
thing by creating results with the map that was current when the code
was generated.  Instead, we should chase pointers to load the right map
from the function's context.

R=verwaest@chromium.org
BUG=v8:3656
LOG=N

Review URL: https://codereview.chromium.org/686063002

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@24987 ce2b1a6d-e550-0410-aec6-3dcde31c8c00