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, 8 insertions, 6 deletions

diff --git a/cli/lsp/diagnostics.rs b/cli/lsp/diagnostics.rs
index 0f96a498b..7b5a30a0e 100644
--- a/cli/lsp/diagnostics.rs
+++ b/cli/lsp/diagnostics.rs
@@ -25,6 +25,8 @@ use deno_core::resolve_url;
 use deno_core::serde::Deserialize;
 use deno_core::serde_json;
 use deno_core::serde_json::json;
+use deno_core::task::spawn;
+use deno_core::task::JoinHandle;
 use deno_core::ModuleSpecifier;
 use deno_graph::Resolution;
 use deno_graph::ResolutionError;
@@ -197,9 +199,9 @@ impl DiagnosticsServer {
 
       runtime.block_on(async {
         let mut token = CancellationToken::new();
-        let mut ts_handle: Option<tokio::task::JoinHandle<()>> = None;
-        let mut lint_handle: Option<tokio::task::JoinHandle<()>> = None;
-        let mut deps_handle: Option<tokio::task::JoinHandle<()>> = None;
+        let mut ts_handle: Option<JoinHandle<()>> = None;
+        let mut lint_handle: Option<JoinHandle<()>> = None;
+        let mut deps_handle: Option<JoinHandle<()>> = None;
         let diagnostics_publisher = DiagnosticsPublisher::new(client.clone());
 
         loop {
@@ -213,7 +215,7 @@ impl DiagnosticsServer {
               diagnostics_publisher.clear().await;
 
               let previous_ts_handle = ts_handle.take();
-              ts_handle = Some(tokio::spawn({
+              ts_handle = Some(spawn({
                 let performance = performance.clone();
                 let diagnostics_publisher = diagnostics_publisher.clone();
                 let ts_server = ts_server.clone();
@@ -265,7 +267,7 @@ impl DiagnosticsServer {
               }));
 
               let previous_deps_handle = deps_handle.take();
-              deps_handle = Some(tokio::spawn({
+              deps_handle = Some(spawn({
                 let performance = performance.clone();
                 let diagnostics_publisher = diagnostics_publisher.clone();
                 let token = token.clone();
@@ -293,7 +295,7 @@ impl DiagnosticsServer {
               }));
 
               let previous_lint_handle = lint_handle.take();
-              lint_handle = Some(tokio::spawn({
+              lint_handle = Some(spawn({
                 let performance = performance.clone();
                 let diagnostics_publisher = diagnostics_publisher.clone();
                 let token = token.clone();