This reverts commit f83d672f.
This reverts commit d5197237.

- Removes unnecessary RwLock and Rc around the op registry table
- Preparation to move resource_table to deno_core::Isolate.
- Towards #3453, #4222

To better reflect changes in error types in JS from #3662 this PR changes 
default error type used in ops from "ErrBox" to "OpError".

"OpError" is a type that can be sent over to JSON; it has all 
information needed to construct error in JavaScript. That
made "GetErrorKind" trait useless and so it was removed altogether.

To provide compatibility with previous use of "ErrBox" an implementation of
"From<ErrBox> for OpError" was added, however, it is an escape hatch and
ops implementors should strive to use "OpError" directly.

* establish basic event loop for workers
* make "self.close()" inside worker
* remove "runWorkerMessageLoop() - instead manually call global function 
  in Rust when message arrives. This is done in preparation for structured clone
* refactor "WorkerChannel" and use distinct structs for internal 
  and external channels;  "WorkerChannelsInternal" and "WorkerHandle"
* move "State.worker_channels_internal" to "Worker.internal_channels"
* add "WorkerEvent" enum for child->host communication; 
  currently "Message(Buf)" and  "Error(ErrBox)" variants are supported
* add tests for nested workers
* add tests for worker throwing error on startup

* rename ThreadSafeState to State
* State stores InnerState wrapped in Rc and RefCell

This change simplifies how we execute V8. Previously V8 Isolates jumped
around threads every time they were woken up. This was overly complex and
potentially hurting performance in a myriad ways. Now isolates run on
their own dedicated thread and never move.

- blocking_json spawns a thread and does not use a thread pool
- op_host_poll_worker and op_host_resume_worker are non-operational
- removes Worker::get_message and Worker::post_message
- ThreadSafeState::workers table contains WorkerChannel entries instead
  of actual Worker instances.
- MainWorker and CompilerWorker are no longer Futures.
- The multi-threaded version of deno_core_http_bench was removed.
- AyncOps no longer need to be Send + Sync

This PR is very large and several tests were disabled to speed
integration:
- installer_test_local_module_run
- installer_test_remote_module_run
- _015_duplicate_parallel_import
- _026_workers

* cli::Worker is base struct to create specialized workers
* add MainWorker
* add CompilerWorker
* refactor WebWorker to use Worker

* split ops/worker.rs into ops/worker_host.rs and ops/web_worker.rs

* refactor js/workers.ts and factor out js/worker_main.ts - entry point for WebWorker runtime

* BREAKING CHANGE: remove support for blob: URL in Worker

* BREAKING CHANGE: remove Deno namespace support and noDenoNamespace option in Worker constructor

* introduce WebWorker struct which is a stripped down version of cli::Worker