fix: use test script from nitro repo

- Follow up to vitejs@076c1b9#r3733642821
- Replaces hard-coded test script with specific test directory
- Requires nitrojs/nitro#4510 to be merged

Author: oneminch

tests/nitro.ts

@@ -7,6 +7,6 @@ export async function test(options: RunOptions) {
 		repo: 'nitrojs/nitro',
 		branch: 'main',
 		build: 'build',
-		test: 'pnpm vitest run test/vite',
+		test: 'test:vite',
 	})
 }