Fix a race condition in a test

It's hard to set this up properly, the cancel request needs to be sent before the GetQueryExecution response with the successful status is returned. Using the number of requests sent works better since it's coupled with the mechanism that blocks the request.

src/test/java/io/burt/athena/AthenaStatementTest.java

@@ -422,9 +422,6 @@ void throwsAnException() {
         class WhenCalledAfterExecute {
             @Test
             void sendsACancelRequest() throws Exception {
-                queryExecutionHelper.queueStartQueryResponse("Q1234");
-                queryExecutionHelper.queueGetQueryExecutionResponse(QueryExecutionState.SUCCEEDED);
-                ResultSet rs = statement.executeQuery("SELECT 1");
                 queryExecutionHelper.blockGetQueryExecutionResponse();
                 queryExecutionHelper.queueStartQueryResponse("Q2345");
                 queryExecutionHelper.queueGetQueryExecutionResponse(QueryExecutionState.RUNNING);
@@ -437,7 +434,8 @@ void sendsACancelRequest() throws Exception {
                     }
                 });
                 runner.start();
-                while (!rs.isClosed()) {
+                while (queryExecutionHelper.getQueryExecutionRequests().size() == 0) {
+                    Thread.sleep(1);
                 }
                 statement.cancel();
                 queryExecutionHelper.unblockGetQueryExecutionResponse();