Reason for revert:
Issue https://bugs.chromium.org/p/chromium/issues/detail?id=677055 . I'll send out a follow-on reland, as it should still be possible to eliminate the redundant type system.
Original issue's description:
> [intl] Remove redundant type checking system
>
> Previously, the Intl implementation tracked types two ways:
> - In the intl_initialized_marker_symbol
> - In various named properties of the intl_impl_object_symbol value
>
> As far as I can tell, these will never disagree with each other,
> modulo bugs in Intl itself. This patch removes the second type
> checking system.
>
> BUG=v8:5751
>
> Review-Url: https://codereview.chromium.org/2591203002
> Cr-Commit-Position: refs/heads/master@{#41941}
> Committed: 0d5561b64dTBR=yangguo@chromium.org
# Not skipping CQ checks because original CL landed more than 1 days ago.
BUG=v8:5751
Review-Url: https://codereview.chromium.org/2601783002
Cr-Commit-Position: refs/heads/master@{#41958}
d20c23cd13