disable next cache for concurrent connect playground builds

Author: aehnh

packages/tests-e2e/src/connect/utils/Playground.ts

@@ -43,6 +43,7 @@ export async function spawnPlaygroundNew(): Promise<PlaygroundInfo> {
     cwd: playgroundDir,
     env: {
       ...process.env,
+      NEXT_PRIVATE_DISABLE_CACHE: '1',
     },
     stdio: 'inherit',
     shell: true,