[1/N][CI] Refactor accuracy test (#5400)

### What this PR does / why we need it?
1. Accuracy testing no longer compares eager and graph modes; instead,
it directly extracts the golden result under the graph mode
configuration (the implicit purpose of this case is to verify whether
modifications affect existing results)
2. Next step: finer-grained supervision of logits/sampler results
### Does this PR introduce _any_ user-facing change?

### How was this patch tested?

- vLLM version: release/v0.13.0
- vLLM main:
254f6b9867

Signed-off-by: wangli <wangli858794774@gmail.com>

tests/e2e/singlecard/utils.py

@@ -0,0 +1,76 @@
+from dataclasses import dataclass, field
+from typing import Optional
+
+from vllm import SamplingParams
+
+from tests.e2e.conftest import VllmRunner
+from tests.e2e.model_utils import check_outputs_equal
+
+PROMPTS_SHORT = [
+    "Hello, my name is", "The president of the United States is",
+    "The capital of France is", "The future of AI is"
+]
+
+# NOTE: Randomly fill the prompt with the requested amount for
+# the specified capture shape to prevent accuracy issues caused by padding
+PROMPTS_LONG = [
+    ('Solve the following math problem step by step.'
+     'The last line of your response should be of the form Answer: '
+     '$Answer (without quotes) where $Answer is the answer to the problem.\n\n'
+     'In triangle $ABC$, $\\sin \\angle A = \\frac{4}{5}$ and $\\angle A < 90^\\circ$. Let $D$'
+     'be a point outside triangle $ABC$ such that $\\angle BAD = \\angle DAC$,'
+     '$\\angle BDC = 90^\\circ$. Suppose $AD = 1$ and $\\frac{BD}{CD} = \\frac{3}{2}$.'
+     'If $AB + AC$ can be expressed in the form $\\frac{a\\sqrt{b}}{c}$,'
+     'where $a, b, c$ are pairwise relatively prime integers, find $a + b + c$.'
+     ),
+    ('Solve the following math problem step by step.'
+     'The last line of your response should be of the form Answer: '
+     '$Answer (without quotes) where $Answer is the answer to the problem.\n\n'
+     'Let $ABCD$ be a unit square in the plane. Points $X$ and $Y$ are chosen'
+     'independently and uniformly at random on the perimeter of $ABCD$.'
+     'If the expected value of the area of triangle $\\triangle AXY$'
+     'can be expressed as $\\frac{m}{n}$, for relatively prime positive'
+     'integers $m$ and $n$, compute $m+n$.'),
+    ('Solve the following math problem step by step.'
+     'The last line of your response should be of the form Answer: '
+     '$Answer (without quotes) where $Answer is the answer to the problem.\n\n'
+     'Let $a, b, c$ be distinct numbers such that the equations $x^2 + ax + 1 = 0$'
+     'and $x^2 + bx + c = 0$ have a common real root, and the equations $x^2 + x + a = 0$'
+     'and $x^2 + cx + b = 0$ also have a common real root.'
+     'Compute the sum $a + b + c$.')
+]
+
+
+@dataclass(frozen=True)
+class LLMTestCase:
+    model: str
+    prompts: list[str]
+    golden_answers: list[str]
+    quantization: Optional[str] = None
+    sampling_params: SamplingParams = field(
+        default_factory=lambda: SamplingParams(
+            max_tokens=32,
+            temperature=0.0,
+            top_p=1.0,
+            top_k=0,
+            n=1,
+        ))
+
+
+def gen_and_valid(runner_kwargs: dict, prompts: list[str],
+                  sampling_params: SamplingParams, golden_answers: list[str]):
+    with VllmRunner(**runner_kwargs) as runner:
+        vllm_aclgraph_outputs = runner.model.generate(
+            prompts=prompts, sampling_params=sampling_params)
+    outputs_gen = []
+    for output in vllm_aclgraph_outputs:
+        outputs_gen.append(([output.outputs[0].index], output.outputs[0].text))
+
+    output_origin = [([0], answer) for answer in golden_answers]
+
+    check_outputs_equal(
+        outputs_0_lst=output_origin,
+        outputs_1_lst=outputs_gen,
+        name_0="output_origin",
+        name_1="outputs_gen",
+    )