[NPU] Phase A calibration: full GSM8K eval for dp_attention mixed-chunk (#38422)

test/registered/npu/basic_function/dp_attn/test_npu_dp_attention.py

@@ -24,7 +24,7 @@ from sglang.test.test_utils import (
 )
 
 register_npu_ci(est_time=400, suite="base-b-test-4-npu-a3")
-register_npu_ci(est_time=400, suite="nightly-4-npu-a3", nightly=True)
+register_npu_ci(est_time=2400, suite="nightly-4-npu-a3", nightly=True)
 
 
 class TestDPAttentionDP2TP2(
@@ -74,6 +74,8 @@ class TestDPAttentionMixedChunk(
     CustomTestCase,
     NPUGSM8KMixin,
 ):
+    # Use full GSM8K dataset to avoid sampling variance.
+    gsm8k_num_examples = 1319
     gsm8k_accuracy_thres = 0.34
 
     @classmethod