notebook resolve should wait for * activated events.

extensions/vscode-notebook-tests/package.json

@@ -6,8 +6,7 @@
   "license": "MIT",
   "private": true,
   "activationEvents": [
-    "*",
-    "onNotebookEditor:notebookCoreTest"
+    "*"
   ],
   "main": "./out/notebookTestMain",
   "enableProposedApi": true,

src/vs/workbench/contrib/notebook/browser/notebookServiceImpl.ts

@@ -203,6 +203,9 @@ export class NotebookService extends Disposable implements INotebookService, ICu
 
 	async canResolve(viewType: string): Promise<boolean> {
 		if (!this._notebookProviders.has(viewType)) {
+			await this.extensionService.whenInstalledExtensionsRegistered();
+			// notebook providers/kernels/renderers might use `*` as activation event.
+			await this.extensionService.activateByEvent(`*`);
 			// this awaits full activation of all matching extensions
 			await this.extensionService.activateByEvent(`onNotebookEditor:${viewType}`);
 		}