From `set_all_contours`, pass `n_cont` and the whole array `cont_list`
to `set_max_speed`, because we are going to define new elements into
this array in `set_max_speed`. `cont_list` in `set_max_speed` becomes
`intent(inout)`.

Because `cont_list` is going to become `intent(inout)`.

Follow commit d540a1f3.

Remove intermediary variables `first_term`, `second_term`, `third_term`.

We keep ssh because we will need it if we call `good_contour`.

Remove dummy argument `ind_targ_extr` of procedure `set_max_speed`,
not used any longer.

Remove component radius4 of derived type eddy and field radius4 of
`outermost_contour.dbf`. They are not used any longer.

Since we now have the test `SHPC_degenerate`.

To replace `Inst_eddies/Tests/Input/SHPC_degenerate`. The motivation
is to have the `cont_list` shapefile, so we can use it with
`test_set_max_speed`.

Because there is no time dimension in
`Inst_eddies/Tests/Input/uv_outermost.nc`, for example.

Abandon the radius4 approach, because the resulting max-speed contours
had speeds significantly lower than those from Matlab and because the
approach with radius4 is difficult to extend to a non
longitude-latitude grid.

Demote dummy arguments nlon and nlat of `input_ssh` to local
variables. nlon and nlat are no longer used in main program unit
`inst_eddies` since commit 03033711.