RFR: 8254691: Enable GitHub actions for jfx repo [v2]

[Kevin Rushforth]

On Fri, 30 Oct 2020 17:05:37 GMT, Johan Vos <jvos at openjdk.org> wrote:

>> Looks good to me. Verified a dummy PR with two commits.
>> Actions executed correctly on both commits. Also verified that test failure is reported correctly and failed test can be found in log under Actions section.
>
> This works fine. I have a minor comment (about using 15.0.1, but since we don't use that in build.properties either, I think it's not an issue), and apart from that, this looks very good.

I'd rather update the boot JDK to 15.0.1 as a follow-on fix, so that it matches the version defined in build.properties. I filed the following follow-on issues:

[JDK-8255714](https://bugs.openjdk.java.net/browse/JDK-8255714): Switch FX build to use JDK 15.0.1 as boot JDK
[JDK-8255712](https://bugs.openjdk.java.net/browse/JDK-8255712): GitHub actions: read boot JDK version and URL from build.properties
[JDK-8255713](https://bugs.openjdk.java.net/browse/JDK-8255713): GitHub actions: JavaFX build should discover Visual Studio compiler on system

-------------

PR: https://git.openjdk.java.net/jfx/pull/338