[BUG] - multiple order dependent flaky tests in `swagger/swagger-generator/generator-core`

### Steps to Reproduce

Several tests in the `swagger/swagger-generator/generator-core` module exhibit **order-dependent (OD) flakiness**. These tests rely on shared state through `SwaggerOperations.generate(...)` and previously used `static` fields inside the test classes. These tests previously used a `static SwaggerOperations` field that was shared across all test methods in the class, and when test methods are executed in different orders, some permutations caused a later test to run after the shared `swaggerOperations` field had already been cleared.

To reproduce:

```bash
mvn edu.illinois.cs:idflakies-maven-plugin:2.0.0:detect -pl swagger/swagger-generator/generator-core -am -Ddt.randomize.rounds=30 -Ddt.detector.original_order.all_must_pass=false
```

### Expected Behavior

Mentioned tests should pass with different orders.

### Servicecomb Version

3.3.0

### Additional Context

_No response_

まず、swagger/swagger-generator/generator-core に対して提供された idflakies Maven コマンドを実行し、SwaggerOperations.generate(...) を呼び出すテストを調査します。テストメソッド間で共有される swaggerOperations の状態がどのように初期化およびクリアされるかを追跡します。ランダム化された実行順序でも、言及されたテストがパスすれば完了です。

索引モデルが issue の本文から書いたものです。