This reverts commit 5320fe8d.

Reason for revert: https://ci.chromium.org/ui/p/v8/builders/ci/V8%20Linux%20-%20debug/38175/overview

Original change's description:
> Reland "[string] Support shared strings in Value{Serializer,Deserializer}"
>
> This is a reland of 3cb4039c
>
> Changes since revert:
> - Fix FLAG_stress_scavenge interaction with shared Isolate
> - Use the shared Isolate's global handles to keep shared values
>   alive in transit during a postMessage
>
> Original change's description:
> > [string] Support shared strings in Value{Serializer,Deserializer}
> >
> > When FLAG_shared_string_table is true, postMessaging strings will share
> > instead of copy.
> >
> > Note that not all operations on shared strings are supported, and shared
> > strings may be slower than non-shared strings for some operations.
> >
> > Bug: v8:12007
> > Change-Id: I3462128e15410d2568868143571571b3025722c1
> > Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3277250
> > Reviewed-by: Toon Verwaest <verwaest@chromium.org>
> > Commit-Queue: Shu-yu Guo <syg@chromium.org>
> > Cr-Commit-Position: refs/heads/main@{#78614}
>
> Bug: v8:12007
> Change-Id: I5d9b99b2dac6f26d5ef046d7aec94f1a1d219419
> Cq-Include-Trybots: luci.v8.try:v8_linux64_tsan_rel_ng
> Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3389533
> Reviewed-by: Camillo Bruni <cbruni@chromium.org>
> Reviewed-by: Dominik Inführ <dinfuehr@chromium.org>
> Reviewed-by: Toon Verwaest <verwaest@chromium.org>
> Commit-Queue: Shu-yu Guo <syg@chromium.org>
> Cr-Commit-Position: refs/heads/main@{#78761}

Bug: v8:12007
Change-Id: Ie8e54b30055324e6592562450b51d5a11e11c9d0
Cq-Include-Trybots: luci.v8.try:v8_linux64_tsan_rel_ng
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3416232
Auto-Submit: Nico Hartmann <nicohartmann@chromium.org>
Bot-Commit: Rubber Stamper <rubber-stamper@appspot.gserviceaccount.com>
Commit-Queue: Nico Hartmann <nicohartmann@chromium.org>
Owners-Override: Nico Hartmann <nicohartmann@chromium.org>
Cr-Commit-Position: refs/heads/main@{#78762}