Suppress a warning in a test

In general we insist that you assign the return of checkRegistrarConsoleLogin
to something, since it's annotated with @CheckReturnValue, but in this
specific test which should always throw the value is unused, so suppress the
"unused" warning.

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=146265522

javatests/google/registry/ui/server/registrar/SessionUtilsTest.java

@@ -112,8 +112,10 @@ public class SessionUtilsTest {
   }
 
   @Test
-  public void testCheckRegistrarConsoleLogin_notLoggedIn_throwsIse() throws Exception {
+  public void testCheckRegistrarConsoleLogin_notLoggedIn_throwsIllegalStateException() 
+      throws Exception {
     thrown.expect(IllegalStateException.class);
+    @SuppressWarnings("unused")
     boolean unused = sessionUtils.checkRegistrarConsoleLogin(req);
   }