Test failure

Friends On https://gitlab.haskell.org/ghc/ghc/-/merge_requests/16447 I'm getting a mysterious failure in the testsuite. The error, below, is not very informative. Can anyone help, please? Thanks Simon Build failed. hadrian/build-cabal --flavour=release -j4 --broken-test= --bignum=gmp test --summary-junit=./junit.xml --test-have-intree-files --test-compiler=/builds/ghc/ghc/_build/install/bin/ghc runtest.opts+= --force-colors runtest.opts+=--unexpected-output-dir=/builds/ghc/ghc/unexpected-test-output failed error: hadrian main testsuite test took 5339 seconds