[CI] List which tests were unsupported

[mortbopet]

Currently, test runs in CI only shows a passed/failed/unsupported split (https://github.com/llvm/circt/actions/runs/3045345694/jobs/4906793030#step:7:68).
In case a test is picked up as unsupported, but one actually would've liked for CI to check it, it would be nice if the test run would explicitly list which tests were unsupported. This should help triaging as well as allow better finger-pointing when that set of unsupported integration tests inevitably grows.

[teqdruid]

There is an llvm-lit flag to list out all the tests and their results.

[mortbopet]

Assuming you refer to https://llvm.org/docs/CommandGuide/lit.html#cmdoption-lit-show-unsupported - that is obviously what we need. Stupid questions aside, the question is then how to pass that lit argument to the ninja check-circt-integration command.

[teqdruid]

I haven't figured that out yet. I usually just run llvm-lit directly on the test directory in the build dir.