GCC-10 build fail on riscv64 (breaks test)

First with a 2GB guest the build OOMed at some point.
Now after 8h of build still only at 87% through the build :-/

Gladly at least a successful build at [1] shows that a skip of that particular test on riscv64 will work

[1]: https://launchpad.net/~ci-train-ppa-service/+archive/ubuntu/4203/+packages

I'll give the build the night to complete for a try at fixing the underlying issue.
But otherwise I'll upload the test skip tomorrow.

I debugged this for quite a while and helped the upstream project to know where things are.
But there is no fix out of that, therefore a test (juts this case) skip it will be for groovy.

This looks to me almost more like a gcc-10 bug breaking the function returns in some way, see [1] for more. For the sake of completeness I'll add a gcc-10 task here.

[1]: https://github.com/dartsim/dart/issues/1482#issuecomment-674053468

Fix uploaded to groovy (as it test built in my PPA before).

This bug was fixed in the package dart - 6.9.2-3ubuntu1

---------------
dart (6.9.2-3ubuntu1) groovy; urgency=medium

  * d/rules: GCC-10 issue on riscv64, skip the one failing test for now
    (LP: #1891440)

 -- Christian Ehrhardt <email address hidden> Tue, 11 Aug 2020 11:35:53 +0200