Error running tests with external PETSc installation

[principejavier]

When installing GridapPETSc with external libraries, i.e. with non-empty JULIA_MPI_BINARY and JULIA_PETSC_LIBRARY, executing the whole set of tests fails even if separate execution of serial and parallel tests succeeds.

In other words,

julia --project=. --color=yes --check-bounds=yes test/sequential/runtests.jl
julia --project=. --color=yes --check-bounds=yes test/mpi/runtests.jl

are both successful but

julia --project=. --color=yes --check-bounds=yes test/runtests.jl

fails to exectute the parallel tests with a message

...
PartitionedArrays: Error During Test at /home/jprincipe/Prog/GridapPETSc.jl/test/mpi/runtests.jl:3
  Got exception outside of a @test
  LoadError: failed process: Process(`mpiexec -n 3 --allow-run-as-root --oversubscribe /home/jprincipe/System/bin/julia-1.7.2/bin/julia -Cnative -J/home/jprincipe/System/bin/julia-1.7.2/lib/julia/sys.so --check-bounds=yes -g1 --color=yes --project=/home/jprincipe/Prog/GridapPETSc.jl/test/mpi/../.. /home/jprincipe/Prog/GridapPETSc.jl/test/mpi/PartitionedArraysTests.jl`, ProcessExited(1)) [1]
...

The execution of the whole set of test is successful when the default installation is used, that is with empty JULIA_MPI_BINARY and JULIA_PETSC_LIBRARY.

@amartinhuertas , @fverdugo any thoughts?

[principejavier]

Fixed at #84