Restrict the max-time in some system tests

[MakisH]

Description

Some tests take much longer than other, and cumulatively the complete release_test is quite long, with limited value of running the complete tests till the end.

A recent snapshot, with some images cached (focus on the "solver time"):

systemtest	success	building time [s]	solver time [s]	fieldcompare time [s]
Quickstart (fluid-openfoam, solid-cpp)	1	224.0	12.6	36.1
Elastic tube 1D (fluid-cpp, solid-cpp)	1	1.5	12.0	4.6
Elastic tube 1D (fluid-python, solid-python)	1	38.8	50.0	5.2
Elastic tube 1D (fluid-cpp, solid-python)	1	1.2	38.9	4.8
Flow over heated plate (fluid-openfoam, solid-nutils)	1	12.1	106.9	4.9
Flow over heated plate (fluid-openfoam, solid-fenics)	1	67.6	59.6	4.9
Flow over heated plate (fluid-openfoam, solid-openfoam)	1	1.2	28.3	4.7
Flow over heated plate nearest projection (fluid-openfoam, solid-openfoam)	1	1.2	38.9	15.2
Flow over heated plate with two meshes (fluid-openfoam, solid-calculix)	1	83.9	273.1	6.7
Perpendicular flap (fluid-openfoam, solid-calculix)	1	1.3	75.0	16.1
Perpendicular flap (fluid-su2, solid-fenics)	1	427.5	469.0	16.0
Perpendicular flap (fluid-openfoam, solid-dealii)	1	99.5	70.5	14.0
Multiple perpendicular flaps (fluid-openfoam, solid-upstream-dealii, solid-downstream-dealii)	1	1.4	202.0	34.0
Heat Exchanger simplified (fluid-top-openfoam, fluid-bottom-openfoam, solid-calculix)	1	1.7	383.0	10.7
Free flow over porous media (free-flow-dumux, porous-media-dumux)	1	330.5	57.1	2.6

This PR restricts the max-time of some cases, while still letting some of the faster solvers run till the end:

• elastic-tube-1d_fluid-cpp_solid-python
  • the C++/Python-only cases are tested in full
• flow-over-heated-plate_fluid-openfoam_solid-nutils
  • the Nutils case takes long
• flow-over-heated-plate-nearest-projection_fluid-openfoam_solid-openfoam
  • the main flow-over-heated-plate is tested in full
• flow-over-heated-plate-two-meshes_fluid-openfoam_solid-calculix
  • the main flow-over-heated-plate is tested in full
• heat-exchanger-simplified_fluid-top-openfoam_fluid-bottom-openfoam_solid-calculix
  • the whole case takes too long, all features are also tested elsewhere
• multiple-perpendicular-flaps_fluid-openfoam_solid-upstream-dealii_solid-downstream-dealii
  • the whole case takes too long, all features are also tested elsewhere
• perpendicular-flap_fluid-openfoam_solid-fenics
• perpendicular-flap_fluid-openfoam_solid-openfoam
• perpendicular-flap_fluid-su2_solid-fenics
  • we already test many perpendicular flaps and all solvers elsewhere.

On top of this, making some cases parallel (introduced in #803) should make the simulation part of the tests even shorter.

I will update the reference results in another PR.