Reference solutions for PnPn test cases

[RonRahaman]

In the legacy test suite, the following test cases were expected to ABORT.

• fs_2/st1.rea, PnPn
• fs_2/std_wv.rea, PnPn
• `fs_hydro/fs_hydro.rea``, PnPn
• peris/peris.rea, PnPn
• solid/solid.rea, PnPn
• var_vis/var_vis.rea, PnPn

The PnPn solver has since been updated, and those test cases are not expected to ABORT. Hence, we should establish reference solutions and add them to the NekTests.py

[RonRahaman]

In a previous conversation, (Nek5000/Nek5000#41), I posted the reference solutions for the corresponding PnPn2 test cases, should anyone be interested:

Test case	Variable	Timestep	Reference value	Tolerance
fs_2/st1	gmres	1.00E+00	0.00000E+00	3.80E+01
fs_2/st1	amp	2.00E+02	6.38241E-01	1.00E-06
fs_2/std_wv	gmres	1.00E+00	0.00000E+00	2.00E+01
fs_2/st1	amp	2.00E+02	1.40329E-01	1.00E-06
fs_hydro	gmres	1.00E+00	0.00000E+00	1.08E+02
fs_hydro	AMP	1.00E+03	-6.46165E-05	2.00E-03
peris	gmres	1.00E+00	0.00000E+00	1.80E+01
solid	error	final	7.82123E-05	1.00E-06
var_vis	gmres	final	0.00000E+00	1.90E+01