[CI][NIXL] Change default block_size for tests (vllm-project#28927)

Signed-off-by: NickLucche <nlucches@redhat.com>

Author: NickLucche

tests/v1/kv_connector/nixl_integration/run_accuracy_test.sh

@@ -49,8 +49,8 @@ NUM_DECODE_INSTANCES=${NUM_DECODE_INSTANCES:-1}   # Default to 1
 PREFILLER_TP_SIZE=${PREFILLER_TP_SIZE:-1}
 DECODER_TP_SIZE=${DECODER_TP_SIZE:-1}
 GPU_MEMORY_UTILIZATION=${GPU_MEMORY_UTILIZATION:-0.2}
-PREFILL_BLOCK_SIZE=${PREFILL_BLOCK_SIZE:-16}
-DECODE_BLOCK_SIZE=${DECODE_BLOCK_SIZE:-16}
+PREFILL_BLOCK_SIZE=${PREFILL_BLOCK_SIZE:-128}
+DECODE_BLOCK_SIZE=${DECODE_BLOCK_SIZE:-128}
 
 # Find the git repository root directory
 GIT_ROOT=$(git rev-parse --show-toplevel)