RFR(T/S) 8231903: [Graal] Update com.oracle.mxtool.junit classes

[Ekaterina Pavlova]

Hi,

please review the following change which syncs com.oracle.mxtool.junit classes with ones from graal ws.
Also
- removed org.graalvm.compiler.core.test.CheckGraalInvariants from test/hotspot/jtreg/ProblemList-graal.txt
   as the test doesn't fail anymore

- updated test/hotspot/jtreg/compiler/graalunit/TestPackages.txt to match latest list of test packages


      JBS: https://bugs.openjdk.java.net/browse/JDK-8231903
   webrev: http://cr.openjdk.java.net/~epavlova//8231903/webrev.00/index.html
  testing: graal unit tests

thanks,
-katya