Spot checking the results:

General test improvement:

• Variant marshalling should be conditioned on supporting COM
• COM testing conditioned on COM support

NativeAOT fixes:

• Need a bit more validation in corner cases
• Need to match strings in exceptions messages

A lot of this would also benefit Mono testing that decided to just not run any of the tests because it's too much of a hassle when this is just one of the 200+ libraries tests that needed to be brought up 2 years ago:

Attached logs here, apparently Github has a 64k character comment limit and this just fails too much: testfails.txt

Cc @AaronRobinsonMSFT @elinor-fung @jkoritzinsky if any of you have cycles to help with some of this.