Unflake two `"use cache"` tests (#91529)
[Flakiness
metric](https://app.datadoghq.com/ci/test/runs?query=test_level%3Atest%20%40git.repository.id%3A%22github.com%2Fvercel%2Fnext.js%22%20%40test.name%3A%28%22use-cache%20should%20cache%20results%20for%20cached%20functions%20imported%20from%20client%20components%22%20OR%20%22use-cache%20should%20cache%20results%20for%20cached%20functions%20passed%20to%20client%20components%22%29%20%40test.status%3A%22fail%22%20%40duration%3A%3E%3D1ns&agg_m=count&agg_m_source=base&agg_t=count&citest_explorer_sort=timestamp%2Casc&cols=%40test.status%2Ctimestamp%2C%40test.suite%2C%40test.name%2C%40duration%2C%40test.service%2C%40git.branch¤tTab=overview&eventStack=&fromUser=false&index=citest&start=1772476060657&end=1773772060657&paused=false)
I'm not sure why these tests recently got much more flaky (they were
somewhat flaky before), but they definitely were missing `retry` blocks
around the assertions after clicking the reset button.