Fix a data race in GraphDatabaseServiceTest

The GraphDatabaseServiceTest.shouldLetDtectedDeadllocksDuringCommitBeThrownInTheirOriginalForm test created a transaction in a companion thread.
It then ended up closing this transaction from that other thread, which resulted in weird non-deterministic exceptions during KernelTransactionImplementation.close().

community/kernel/src/main/java/org/neo4j/kernel/impl/locking/community/LockManagerImpl.java

@@ -129,7 +129,7 @@ private void assertValidArguments( Object resource, Object tx )
     {
         if ( resource == null || tx == null )
         {
-            throw new IllegalResourceException( "Null parameter" );
+            throw new IllegalResourceException( "Null parameter: resource = " + resource + ", tx = " + tx );
         }
     }
 

community/kernel/src/test/java/org/neo4j/graphdb/GraphDatabaseServiceTest.java

@@ -19,16 +19,16 @@
  */
 package org.neo4j.graphdb;
 
-import java.util.concurrent.CountDownLatch;
-import java.util.concurrent.Executors;
-import java.util.concurrent.Future;
-import java.util.concurrent.atomic.AtomicReference;
-
 import org.hamcrest.CoreMatchers;
 import org.junit.Assert;
 import org.junit.Rule;
 import org.junit.Test;
 
+import java.util.concurrent.CountDownLatch;
+import java.util.concurrent.Executors;
+import java.util.concurrent.Future;
+import java.util.concurrent.atomic.AtomicReference;
+
 import org.neo4j.kernel.DeadlockDetectedException;
 import org.neo4j.kernel.impl.MyRelTypes;
 import org.neo4j.test.CleanupRule;
@@ -293,7 +293,9 @@ public void shouldLetDetectedDeadlocksDuringCommitBeThrownInTheirOriginalForm()
         }
         finally
         {
-            t2Tx.close();
+            t2n2Wait.get();
+            t2.execute( close( t2Tx ) );
+            t2.close();
         }
     }
 
@@ -323,6 +325,19 @@ public Object doWork( Void state ) throws Exception
         };
     }
 
+    private WorkerCommand<Void, Void> close( final Transaction tx )
+    {
+        return new WorkerCommand<Void,Void>()
+        {
+            @Override
+            public Void doWork( Void state ) throws Exception
+            {
+                tx.close();
+                return null;
+            }
+        };
+    }
+
     private Relationship createRelationship( Node node )
     {
         try ( Transaction tx = node.getGraphDatabase().beginTx() )