refactor(core): bake single-thread assumptions into spawn/spawn_blocking (#19056)

Partially supersedes #19016.

This migrates `spawn` and `spawn_blocking` to `deno_core`, and removes
the requirement for `spawn` tasks to be `Send` given our single-threaded
executor.

While we don't need to technically do anything w/`spawn_blocking`, this
allows us to have a single `JoinHandle` type that works for both cases,
and allows us to more easily experiment with alternative
`spawn_blocking` implementations that do not require tokio (ie: rayon).

Async ops (+~35%):

Before: 

```
time 1310 ms rate 763358
time 1267 ms rate 789265
time 1259 ms rate 794281
time 1266 ms rate 789889
```

After:

```
time 956 ms rate 1046025
time 954 ms rate 1048218
time 924 ms rate 1082251
time 920 ms rate 1086956
```

HTTP serve (+~4.4%):

Before:

```
Running 10s test @ http://localhost:4500
  2 threads and 10 connections
  Thread Stats   Avg      Stdev     Max   +/- Stdev
    Latency    68.78us   19.77us   1.43ms   86.84%
    Req/Sec    68.78k     5.00k   73.84k    91.58%
  1381833 requests in 10.10s, 167.36MB read
Requests/sec: 136823.29
Transfer/sec:     16.57MB
```

After:

```
Running 10s test @ http://localhost:4500
  2 threads and 10 connections
  Thread Stats   Avg      Stdev     Max   +/- Stdev
    Latency    63.12us   17.43us   1.11ms   85.13%
    Req/Sec    71.82k     3.71k   77.02k    79.21%
  1443195 requests in 10.10s, 174.79MB read
Requests/sec: 142921.99
Transfer/sec:     17.31MB
```

Suggested-By: alice@ryhl.io
Co-authored-by: Bartek Iwańczuk <biwanczuk@gmail.com>

1 files changed, 3 insertions, 3 deletions

diff --git a/ext/net/ops_tls.rs b/ext/net/ops_tls.rs
index b9b37b328..7f451d0a8 100644
--- a/ext/net/ops_tls.rs
+++ b/ext/net/ops_tls.rs
@@ -26,6 +26,7 @@ use deno_core::futures::task::Waker;
 use deno_core::op;
 
 use deno_core::parking_lot::Mutex;
+use deno_core::task::spawn;
 use deno_core::AsyncRefCell;
 use deno_core::AsyncResult;
 use deno_core::ByteString;
@@ -74,7 +75,6 @@ use tokio::io::AsyncWriteExt;
 use tokio::io::ReadBuf;
 use tokio::net::TcpListener;
 use tokio::net::TcpStream;
-use tokio::task::spawn_local;
 
 #[derive(Copy, Clone, Debug, Eq, PartialEq)]
 enum Flow {
@@ -224,9 +224,9 @@ impl Drop for TlsStream {
     let use_linger_task = inner.poll_close(&mut cx).is_pending();
 
     if use_linger_task {
-      spawn_local(poll_fn(move |cx| inner.poll_close(cx)));
+      spawn(poll_fn(move |cx| inner.poll_close(cx)));
     } else if cfg!(debug_assertions) {
-      spawn_local(async {}); // Spawn dummy task to detect missing LocalSet.
+      spawn(async {}); // Spawn dummy task to detect missing runtime.
     }
   }
 }