This reverts commit 4968b2c4.

Reason for revert: Speculative revert for severe perf regression
https://bugs.chromium.org/p/chromium/issues/detail?id=716468#c3

Original change's description:
> [intl] Switch to using declared accessors
> 
> This patch cleans up the Intl code by switching to using declared
> accessors, rather than embedder fields, for holding references to
> ICU objects. Additionally:
> - Rename classes to be more similar to how other classes are named
> - Make some unreachable paths into check-fails, rather than throwing
>   JS exceptions
> - Move some macros from objects-inl.h into object-macros.h, to allow
>   the implementation here to not touch objects.h
> - Some setup logic is moved from runtime-i18n.cc to i18n.cc.
> 
> This patch leaves type tags as they are; a future patch should move
> from a special Intl type tagging system to object types as other system
> objects use. Future patches should also move more logic to i18n.cc
> 
> BUG=v8:5402,v8:5751,v8:6057
> CQ_INCLUDE_TRYBOTS=master.tryserver.v8:v8_linux_noi18n_rel_ng
> 
> Change-Id: Ia9cbb25cf8f52662e3deb15e64179d792c10842c
> Reviewed-on: https://chromium-review.googlesource.com/479651
> Commit-Queue: Daniel Ehrenberg <littledan@chromium.org>
> Reviewed-by: Adam Klein <adamk@chromium.org>
> Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#44804}

TBR=adamk@chromium.org,marja@chromium.org,mstarzinger@chromium.org,littledan@chromium.org,jwolfe@igalia.com
# Not skipping CQ checks because original CL landed > 1 day ago.
BUG=v8:5402,v8:5751,v8:6057
CQ_INCLUDE_TRYBOTS=master.tryserver.v8:v8_linux_noi18n_rel_ng

Change-Id: I7a45d7def1f1de0f21e3efb7de9b31f6bcfea46d
Reviewed-on: https://chromium-review.googlesource.com/490328Reviewed-by: Daniel Ehrenberg <littledan@chromium.org>
Commit-Queue: Daniel Ehrenberg <littledan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#44992}