Unrelated output sneaks into T5435_v_asm_a output

Bizarrely, T5435_v_asm_a fails with unexpected output on Windows when testsuite/ghc-config/ghc-config doesn't exist:

$ rm testsuite/ghc-config/ghc-config
$ hadrian/build-cabal -j9  --docs=no-haddocks  test  --flavour=validate  --only='T5435_v_asm_a '

...

=====> 1 of 1 [0, 0, 0]
Actual stdout output differs from expected:
--- "C:/Users/ben/AppData/Local/Temp/ghctest-ejnzps4n/test   spaces/testsuite/tests/rts/linker/T5435_v_asm_a.run/T5435_v_asm_a.stdout-mingw32.normalised"       2022-08-18 12:04:43.166524200 -0400
+++ "C:/Users/ben/AppData/Local/Temp/ghctest-ejnzps4n/test   spaces/testsuite/tests/rts/linker/T5435_v_asm_a.run/T5435_v_asm_a.run.stdout.normalised"   2022-08-18 12:04:43.167528600 -0400
@@ -1,3 +1,4 @@
+[2 of 2] Linking C:/msys64/home/ben/ghc/testsuite/ghc-config/ghc-config
 success
 ctors1
 ctors2
*** unexpected failure for T5435_v_asm_a(normal)