Remove unused suppressions, throw if we expect to fail

Bug: 185205222
Change-Id: Ia910fc30bd71f78e49707cafb11291003e8155e7
diff --git a/src/test/java/com/android/tools/r8/R8RunArtTestsTest.java b/src/test/java/com/android/tools/r8/R8RunArtTestsTest.java
index 7676fe1..9a95fa7 100644
--- a/src/test/java/com/android/tools/r8/R8RunArtTestsTest.java
+++ b/src/test/java/com/android/tools/r8/R8RunArtTestsTest.java
@@ -2423,8 +2423,7 @@
         expectException(CompilationError.class);
         throw new CompilationError(e.getMessage(), e);
       }
-      System.err.println("Should have failed R8/D8 compilation with a CompilationError.");
-      return;
+      throw new RuntimeException("Should have failed R8/D8 compilation with a CompilationError.");
     } else if (specification.failsWithX8) {
       expectException(Throwable.class);
       executeCompilerUnderTest(