test/sequential/ElasticityDriver.jl fails with PETSc compiled in DEBUG mode on my machine

@fverdugo ... test/sequential/ElasticityDriver.jl fails with PETSc compiled in DEBUG mode on my machine

The error is:

```
[0]PETSC ERROR: --------------------- Error Message --------------------------------------------------------------
[0]PETSC ERROR: Invalid argument
[0]PETSC ERROR: Vector 0 must have 2-norm of 1.0, it is 27.
[0]PETSC ERROR: See https://petsc.org/release/faq/ for trouble shooting.
[0]PETSC ERROR: Petsc Release Version 3.15.4, Sep 01, 2021
[0]PETSC ERROR: GridapPETSc on a x86_64 named sistemas-ThinkPad-X1-Carbon-6th by amartin Sat Nov 13 16:14:08 2021
[0]PETSC ERROR: Configure options --with-cc=mpicc --with-cxx=mpicxx --with-fc=mpif90 -with-blaslapack-dir=/opt/intel/compilers_and_libraries_2020.0.166/linux/mkl --download-mumps --download-scalapack --download-parmetis --download-metis --download-ptscotch --with-debugging --with-x=0 --with-shared-libraries=1 --with-mpi=1 --with-64-bit-indices
[0]PETSC ERROR: #1 MatNullSpaceCreate() at /home/amartin/software_installers/petsc-3.15.4-build-dbg-gnu9-mpi/src/mat/interface/matnull.c:265
ElasticityDriver: Error During Test at /home/amartin/git-repos/GridapPETSc.jl/test/sequential/runtests.jl:19
Got exception outside of a @test
LoadError: Petsc returned with error code: 62
Stacktrace:
[1] macro expansion
@ ~/git-repos/GridapPETSc.jl/src/Config.jl:88 [inlined]
[2] (::Main.GridapPETScSequentialTests.ElasticityDriver.var"#1#9")()
@ Main.GridapPETScSequentialTests.ElasticityDriver ~/git-repos/GridapPETSc.jl/test/sequential/ElasticityDriver.jl:79
[3] with(f::Main.GridapPETScSequentialTests.ElasticityDriver.var"#1#9"; kwargs::Base.Iterators.Pairs{Symbol, Vector{SubString{String}}, Tuple{Symbol}, NamedTuple{(:args,), Tuple{Vector{SubString{String}}}}})
@ GridapPETSc ~/git-repos/GridapPETSc.jl/src/Environment.jl:38
[4] top-level scope
@ ~/git-repos/GridapPETSc.jl/test/sequential/ElasticityDriver.jl:50
[5] include(mod::Module, _path::String)
```

I tried to normalize the rigid body motion vectors. This error above disappears, but we get a new one. Namely:

```
[0]PETSC ERROR: --------------------- Error Message --------------------------------------------------------------
[0]PETSC ERROR: Invalid argument
[0]PETSC ERROR: Vector 0 must have 2-norm of 1.0, it is 27.
[0]PETSC ERROR: See https://petsc.org/release/faq/ for trouble shooting.
[0]PETSC ERROR: Petsc Release Version 3.15.4, Sep 01, 2021
[0]PETSC ERROR: GridapPETSc on a x86_64 named sistemas-ThinkPad-X1-Carbon-6th by amartin Sat Nov 13 16:14:08 2021
[0]PETSC ERROR: Configure options --with-cc=mpicc --with-cxx=mpicxx --with-fc=mpif90 -with-blaslapack-dir=/opt/intel/compilers_and_libraries_2020.0.166/linux/mkl --download-mumps --download-scalapack --download-parmetis --download-metis --download-ptscotch --with-debugging --with-x=0 --with-shared-libraries=1 --with-mpi=1 --with-64-bit-indices
[0]PETSC ERROR: #1 MatNullSpaceCreate() at /home/amartin/software_installers/petsc-3.15.4-build-dbg-gnu9-mpi/src/mat/interface/matnull.c:265
ElasticityDriver: Error During Test at /home/amartin/git-repos/GridapPETSc.jl/test/sequential/runtests.jl:19
Got exception outside of a @test
LoadError: Petsc returned with error code: 62
Stacktrace:
[1] macro expansion
@ ~/git-repos/GridapPETSc.jl/src/Config.jl:88 [inlined]
[2] (::Main.GridapPETScSequentialTests.ElasticityDriver.var"#1#9")()
@ Main.GridapPETScSequentialTests.ElasticityDriver ~/git-repos/GridapPETSc.jl/test/sequential/ElasticityDriver.jl:79
[3] with(f::Main.GridapPETScSequentialTests.ElasticityDriver.var"#1#9"; kwargs::Base.Iterators.Pairs{Symbol, Vector{SubString{String}}, Tuple{Symbol}, NamedTuple{(:args,), Tuple{Vector{SubString{String}}}}})
@ GridapPETSc ~/git-repos/GridapPETSc.jl/src/Environment.jl:38
[4] top-level scope
@ ~/git-repos/GridapPETSc.jl/test/sequential/ElasticityDriver.jl:50
[5] include(mod::Module, _path::String)
@ Base ./Base.jl:386
[6] include
@ ~/git-repos/GridapPETSc.jl/test/sequential/runtests.jl:1 [inlined]
```

does it ring a bell? The rigid body motions seem to be well defined in the driver (3xrotations + 3xtranslations).

At present we are not able to reproduce this error in Github actions as we are using PETSc_jll which comes with PETSc compiled in release mode.