Correct handling of overlapping NNC and EDITNNC

[daavid00]

Avoid writing twice to the INIT the NNCTRANS.

Before merging, adding this deck to the regression tests:

OPM/opm-tests#1502

Depends on OPM/opm-common#5025

Closes #6865

[akva2]

why capture as pointer? capture as ref, ie, [&outputNnc = this->outputNnc_]

[daavid00]

Thanks, PR updated.

[daavid00]

In draft mode until how to handle this is decided in #6865

[blattms]

I don't think this correct if the value in EDITNNC is not 0.

Because we apply and internalize EDITNNC for an input NNC in OPM/opm-common#5025, we will reapply the value in EDITNNC in the EDIT section another time in Transmissibility::applyEditNncToGridTrans. Note that there we apply one factor that incorporates all EDITNNC internalized from the GRID/EDIT section and specified in the SCHEDULE section.

I don't have the complete picture, yet, but maybe we should not apply EDITNNC to input NNCs in opm-common and always internalize. Then all NNCs are treated equal. Not sure whether we need to do something addtional for output, though,

[blattms]

I am not sure what this change does and whether it is correct.

For each cell pair in (at least) CpGrid there is only one intersection, even if there is an explicitly specified NNC and one that is created because of the grid topology. (Because of this and the additional output of those NNCs, we substract the transmissibility of the explicitly specified NNC below).

If I understand this change correctly. then `alreadyAssigned returns true if there was an NNC in the deck for this cell pair. Doesn't this mean that the transmissibility of an NNC created by the topology of the grid is not output at all if there was also an explicit NNC in the deck?

[daavid00]

In master using the test case in OPM/opm-tests#1502 (i.e., internally the generated NNC has a value of 0.10000000E+01) with:

NNC 1 1 1 2 1 2 6666, EDITNNCR 1 1 1 2 1 2 9999 -> TRANNNC 0.99990000E+04 0.33330000E+04
NNC 1 1 1 2 1 2 6666, EDITNNC   1 1 1 2 1 2 10 -> TRANNNC 0.66661000E+05 0.10000000E+01

Here in EclGenericWriter_impl.hpp the total transmissibility is assigned, and with this PR we avoid writing duplicated values, i.e., with these PRs:

NNC 1 1 1 2 1 2 6666, EDITNNCR 1 1 1 2 1 2 9999 -> TRANNNC 0.99990000E+04
NNC 1 1 1 2 1 2 6666, EDITNNC 1 1 1 2 1 2 10 -> TRANNNC 0.66760000E+04

On a related note I still think EDITNNC/EDITNNCR should be applied only to internally generated NNCs and not the ones given in the deck using the keyword NNC. I would be happy to update the code in different PRs if that is the case.