This reverts commit a0728e86.

Reason for revert: Times out on Windows & debug builds - https://ci.chromium.org/p/v8/builders/ci/V8%20Win32%20-%20nosnap%20-%20shared/34484

Original change's description:
> [d8] Remove maximum workers limitation
> 
> This CL refactors the lifetime management of the v8::Worker C++ object
> and in the process lifts the 100 maximum worker limitation. To do this,
> it uses a Managed<v8::Worker> heap object and attaches the managed to
> the API worker object.
> 
> R=​mstarzinger@chromium.org
> BUG=v8:9524
> 
> Change-Id: I279b7aeb6645a87f9108ee6f572105739721cef4
> Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1715453
> Commit-Queue: Ben Titzer <titzer@chromium.org>
> Reviewed-by: Clemens Hammacher <clemensh@chromium.org>
> Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#62932}

TBR=mstarzinger@chromium.org,titzer@chromium.org,clemensh@chromium.org

Change-Id: I3a27937cba13b5413390f49268a107c184515153
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: v8:9524
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1720590Reviewed-by: Maya Lekova <mslekova@chromium.org>
Commit-Queue: Maya Lekova <mslekova@chromium.org>
Cr-Commit-Position: refs/heads/master@{#62937}