lsp: Wait for shutdown response before sending exit notification (#33417)

Follow up: #18634

Closes #33328

Release Notes:

- Fixed language server shutdown process to prevent race conditions and
improper termination by waiting for shutdown confirmation before closing
connections.

crates/vim/src/test.rs

@@ -1006,8 +1006,6 @@ async fn test_rename(cx: &mut gpui::TestAppContext) {
     cx.assert_state("const afterˇ = 2; console.log(after)", Mode::Normal)
 }
 
-// TODO: this test is flaky on our linux CI machines
-#[cfg(target_os = "macos")]
 #[gpui::test]
 async fn test_remap(cx: &mut gpui::TestAppContext) {
     let mut cx = VimTestContext::new(cx, true).await;
@@ -1048,8 +1046,6 @@ async fn test_remap(cx: &mut gpui::TestAppContext) {
     cx.simulate_keystrokes("g x");
     cx.assert_state("1234fooˇ56789", Mode::Normal);
 
-    cx.executor().allow_parking();
-
     // test command
     cx.update(|_, cx| {
         cx.bind_keys([KeyBinding::new(