修改后端代码，实现条件流程校验阶段对多节点的支持

Author: qq_62395577

app-builder/waterflow/java/waterflow-service/src/main/java/modelengine/fit/waterflow/flowsengine/domain/flows/validators/rules/nodes/ParallelNodeRule.java

@@ -25,6 +25,6 @@ public class ParallelNodeRule implements NodeRule {
      */
     @Override
     public void apply(FlowNode flowNode) {
-        Validation.same(flowNode.getEvents().size(), EXPECT_EVENT_SIZE, exception("parallel node event size"));
+        Validation.greaterThanOrEquals(flowNode.getEvents().size(), EXPECT_EVENT_SIZE, exception("parallel node event size"));
     }
 }

app-builder/waterflow/java/waterflow-service/src/main/java/modelengine/fit/waterflow/flowsengine/domain/flows/validators/rules/nodes/StartNodeRule.java

@@ -27,7 +27,7 @@ public class StartNodeRule implements NodeRule {
      */
     @Override
     public void apply(FlowNode flowNode) {
-        Validation.same(flowNode.getEvents().size(), EXPECT_EVENT_SIZE,
+        Validation.greaterThanOrEquals(flowNode.getEvents().size(), EXPECT_EVENT_SIZE,
                 () -> new WaterflowParamException(INVALID_START_NODE_EVENT_SIZE));
         validateNull(flowNode.getJober(), "start node jober should be null");
         validateTriggerMode(flowNode, "start node trigger mode");

app-builder/waterflow/java/waterflow-service/src/main/java/modelengine/fit/waterflow/flowsengine/domain/flows/validators/rules/nodes/StateNodeRule.java

@@ -27,7 +27,7 @@ public class StateNodeRule implements NodeRule {
      */
     @Override
     public void apply(FlowNode flowNode) {
-        Validation.same(flowNode.getEvents().size(), EXPECT_EVENT_SIZE,
+        Validation.greaterThanOrEquals(flowNode.getEvents().size(), MINIMUM_EVENT_SIZE,
                 () -> new WaterflowParamException(INVALID_STATE_NODE_EVENT_SIZE));
         if (!flowNode.getTriggerMode().isAuto()) {
             Validation.notNull(flowNode.getTask(), exception("Flow node task error"));