testsuite: Fix cabal01 for real this time
testsuite: Fix cabal01 for real this time

Somehow the previous version passed on master but fails on ghc-8.2.
Will look deeper later.

(cherry picked from commit a6774e1d70f18f5c05279453d62fb3bcc7f07d7e)

ezyang/ghc,shlevy/ghc,sdiehl/ghc,shlevy/ghc,ezyang/ghc,sdiehl/ghc,shlevy/ghc,sdiehl/ghc,shlevy/ghc,shlevy/ghc,sdiehl/ghc,shlevy/ghc,sdiehl/ghc,sdiehl/ghc,shlevy/ghc,ezyang/ghc,ezyang/ghc,ezyang/ghc,sdiehl/ghc,ezyang/ghc,ezyang/ghc