Spec decode support for V1 Engine (#874)

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Make spec decode support for V1 Engine
- Currently, Ascend does not support the triton kernel. PyTorch is used
to rewrite the `rejection_sampler.py` triton kernel. However, PyTorch is
not as good as Triton. Therefore, ascend c is used to implement the
function in the future.
- Currently, spec decode supports only the ngram algorithm. The eagle
algorithm needs to be further adapted.
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Not change user facing.

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test by `tests/singlecard/spec_decode/e2e/test_v1_spec_decode.py` and
`tests/sample/test_rejection_sampler.py`, test base function of
rejection sampler and e2e function of spec decode.

Signed-off-by: ponix-j <657511300@qq.com>

.github/workflows/vllm_ascend_test.yaml

@@ -161,8 +161,9 @@ jobs:
         if: steps.filter_spec_decode.outputs.speculative_tests_changed == 'true' || github.event_name == 'schedule'
         run: |
           if [[ "${{ matrix.os }}" == "linux-arm64-npu-1" ]]; then
+            VLLM_USE_MODELSCOPE=true pytest -sv tests/singlecard/spec_decode/e2e/test_v1_spec_decode.py
             pytest -sv tests/singlecard/spec_decode/e2e/test_mtp_correctness.py  # it needs a clean process
-            pytest -sv tests/singlecard/spec_decode --ignore=tests/singlecard/spec_decode/e2e/test_mtp_correctness.py
+            pytest -sv tests/singlecard/spec_decode --ignore=tests/singlecard/spec_decode/e2e/test_mtp_correctness.py --ignore=tests/singlecard/spec_decode/e2e/test_v1_spec_decode.py
           fi
 
       - name: Run vllm-project/vllm test for V0 Engine