fragile tests

Hi devs, I believe threadstatus-9333 is more fragile than it's listed as. See https://gitlab.haskell.org/rae/ghc/-/jobs/163182 https://gitlab.haskell.org/rae/ghc/-/jobs/163182, where I haven't been anywhere near this area of the code... Also, on a separate test, I found that compact_gc got killed. See https://gitlab.haskell.org/rae/ghc/-/jobs/163526 https://gitlab.haskell.org/rae/ghc/-/jobs/163526. Should these be fragile? Thanks, Richard