make sure to clean up the CancelThread. Sometimes this test fails and then the…

make sure to clean up the CancelThread. Sometimes this test fails and then the cancel thread hangs around.

h2/src/test/org/h2/test/jdbc/TestCancel.java

@@ -177,12 +177,15 @@ public class TestCancel extends TestBase {
             CancelThread cancel = new CancelThread(query, i);
             visit(0);
             cancel.start();
+            try {
                 Thread.yield();
                 assertThrows(ErrorCode.STATEMENT_WAS_CANCELED, query).
                         executeQuery("SELECT VISIT(ID), (SELECT SUM(X) " +
                                 "FROM SYSTEM_RANGE(1, 10000) WHERE X<>ID) FROM TEST ORDER BY ID");
+            } finally {
                cancel.stopNow();
                cancel.join();
+            }
             if (lastVisited == 0) {
                 i += 10;
             } else {