testsuite: Mark T13340 as fixed
testsuite: Mark T13340 as fixed

It was fixed by 55efc9718b520ef354e32c15c4b49cdfecce412f

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