JavaScript: Add runnable tests (#12118)

https://github.com/zed-industries/zed/assets/62463826/2912c940-bd00-483d-9ce7-df1a2539560a


Release Notes:

- Added runnable tests for JavaScript & Typescript files.
- Added task to run selected javascript code.

crates/languages/src/lib.rs

@@ -7,6 +7,7 @@ use rust_embed::RustEmbed;
 use settings::SettingsStore;
 use smol::stream::StreamExt;
 use std::{str, sync::Arc};
+use typescript::typescript_task_context;
 use util::{asset_str, ResultExt};
 
 use crate::{
@@ -146,13 +147,15 @@ pub fn init(
         "typescript",
         vec![Arc::new(typescript::TypeScriptLspAdapter::new(
             node_runtime.clone()
-        ))]
+        ))],
+        typescript_task_context()
     );
     language!(
         "javascript",
         vec![Arc::new(typescript::TypeScriptLspAdapter::new(
             node_runtime.clone()
-        ))]
+        ))],
+        typescript_task_context()
     );
     language!(
         "jsdoc",