Update test/runtests.jl

Co-authored-by: Valentin Churavy <[email protected]>

Author: michel2323

test/runtests.jl

@@ -1766,9 +1766,7 @@ end
     testdir = @__DIR__
     # Test parsing
     include("mpi.jl")
-    mpiexec() do cmd
-        run(`$cmd -n 2 $(Base.julia_cmd()) --project=$testdir $testdir/mpi.jl`)
-    end
+    success(pipeline(`$(mpiexec()) -n 2 $(Base.julia_cmd()) --project=$testdir $testdir/mpi.jl`; stderr))
     @test true
 end