[Misc]: Re-Enable the disabled unittest in PR 950

[ganyi1996ppo]

Tracking Disabled unittest.

PR #950 disabled serveral unittest in the vllm-ascend, for the kv cache format change may lead to OOM issue which will be resolved after the newest CANN release. This issue will trace the re-enable process of those test.

• test_generate_with_allgather
• test_generate_with_alltoall
• test_models_distributed_DeepSeekV3_dbo
• test_models_distributed_DeepSeek_W8A8

[Yikun]

FYI: CANN 8.2.RC1 already upgraded: #1653