Fix flaky rsc test (#38573)
Fix flaky rsc test (#38573)

x-ref: https://github.com/vercel/next.js/runs/7306197700?check_suite_focus=true#step:9:835
JeromeFitz/next.js,JeromeFitz/next.js,JeromeFitz/next.js,JeromeFitz/next.js