Skara github bot and testing

[Vladimir Kempik]

Hello
I just found useful some possible addition to github bot.
Currently openjdk’s GitHub CI tests only specific sets of tests ( right now only tier1).
It would be nice to have it also test any testcase which was modified by the commit.
This would be useful for clean backports to make sure the jdk with the patch passes updated/new test (without making local build)
Not really sure if it’s for Skara or CI.

Regards, Vladimir