RFR: 8201794: [Graal] add dummy HotSpotGraalManagement class

[Doug Simon]

Right after pushing the change for JDK-8187490, I noticed that the mach5 build had 2 CTW test failures due to jdk.internal.vm.compiler.management now being an empty module. This will be fixed in the next Graal update but the failing tests should be fixed in the meantime.

http://cr.openjdk.java.net/~dnsimon/8201794/
https://bugs.openjdk.java.net/browse/JDK-8201794

I'm running mach5 now to ensure the regressions are fixed and no other regressions occur.

-Doug