refactor: Use Tokio's single-threaded runtime (#3844)

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/ops/files.rs

@@ -139,7 +139,7 @@ fn op_open(
     let buf = futures::executor::block_on(fut)?;
     Ok(JsonOp::Sync(buf))
   } else {
-    Ok(JsonOp::Async(fut.boxed()))
+    Ok(JsonOp::Async(fut.boxed_local()))
   }
 }
 
@@ -211,6 +211,6 @@ fn op_seek(
     let buf = futures::executor::block_on(fut)?;
     Ok(JsonOp::Sync(buf))
   } else {
-    Ok(JsonOp::Async(fut.boxed()))
+    Ok(JsonOp::Async(fut.boxed_local()))
   }
 }