Modal multiport

[edwardalee]

Modal models previously lacked support for multiports and banks. This fixes that problem.
Closes issue #2418.

[Depetrol]

This looks good to me and solves the issue nicely. We might have to bump reactor-c again before merging, otherwise the newly introduced test in #2423 would fail.

[edwardalee]

The test failure here requires this merge: lf-lang/reactor-c#490
which in turn requires this merge: #2424

[OmerMajNition]

lgtm, I've tried with few tests, solves this particular problem

[lhstrh]

Note that the Python failure indicates a segfault...

[Depetrol]

This is related to the newly introduced test in #2423. I'm actively investigating this concurrently bug (see here). Meanwhile, this test should be moved into failing.

[edwardalee]

Note that the Python failure indicates a segfault...

It has always been the case that when a Python program fails, the main process segfaults. The segfault occurs after the failure, not before. It is really inelegant, but I haven't been able to figure out how to track it down.