Investigate failing `ComputeIntegrationTest.VerifyRetrievalMalformedCamelCaseJsonField`

This [job log](https://pantheon.corp.google.com/cloud-build/builds;region=us-east1/158a5019-c1b2-41db-8d69-cb89f3de435a?project=cloud-cpp-testing-resources&e=-13802955&mods=logs_tg_prod) shows failing integration tests:

```
Step #2: [ FAILED ] ComputeIntegrationTest.VerifyRetrievalMalformedCamelCaseJsonField (377 ms)
Step #2: [ RUN ] ComputeIntegrationTest.PaginatedMapField
Step #2: [ OK ] ComputeIntegrationTest.PaginatedMapField (500 ms)
Step #2: [ RUN ] ComputeIntegrationTest.VerifyUpdateSendsUpdateMaskParameter
Step #2: [ OK ] ComputeIntegrationTest.VerifyUpdateSendsUpdateMaskParameter (4819 ms)
Step #2: [----------] 6 tests from ComputeIntegrationTest (11932 ms total)
...
Step #2: //google/cloud/compute/integration_tests:compute_integration_test FAILED in 3 out of 3 in 17.6s
```

从链接的 Cloud Build 作业日志以及失败中提到的 ComputeIntegrationTest.VerifyRetrievalMalformedCamelCaseJsonField 测试开始。重现 Compute 集成测试目标，并调查为什么该测试失败，而 PaginatedMapField 和 VerifyUpdateSendsUpdateMaskParameter 能够通过；当该目标能够稳定通过时即视为完成。

由索引模型根据 Issue 内容生成。