Revert "Dispose logger on extension deactivation"

This reverts commit 13872543e0.
That commit was wrong because we use-after-free the logger

editors/code/src/util.ts

@@ -18,10 +18,6 @@ export const log = new class {
     private enabled = true;
     private readonly output = vscode.window.createOutputChannel("Rust Analyzer Client");
 
-    dispose() {
-        log.output.dispose();
-    }
-
     setEnabled(yes: boolean): void {
         log.enabled = yes;
     }