ci: fix windows and linux ui test

Author: wenytang-ms

test/index.ts

@@ -12,7 +12,7 @@ async function main(): Promise<void> {
         // test fails in macOS since the limitation of path length
         // See: https://github.com/microsoft/vscode/issues/86382#issuecomment-593765388
         const userDir = fs.mkdtempSync(path.join(os.tmpdir(), "vscode-user"));
-        const vscodeExecutablePath = await downloadAndUnzipVSCode();
+        const vscodeExecutablePath = await downloadAndUnzipVSCode('stable');
 
         // Resolve redhat.java dependency
         const [cli, ...args] = resolveCliArgsFromVSCodeExecutablePath(vscodeExecutablePath);