Update test case parameter to have the throughput above 8.0 (#19994)

Signed-off-by: Qiliang Cui <derrhein@gmail.com>

Author: QiliangCui

.buildkite/scripts/tpu/config_v6e_1.env

@@ -4,8 +4,8 @@ CONTAINER_NAME=vllm-tpu
 
 # vllm config
 MODEL=meta-llama/Llama-3.1-8B-Instruct
-MAX_NUM_SEQS=512
-MAX_NUM_BATCHED_TOKENS=512
+MAX_NUM_SEQS=256
+MAX_NUM_BATCHED_TOKENS=1024
 TENSOR_PARALLEL_SIZE=1
 MAX_MODEL_LEN=2048
 DOWNLOAD_DIR=/mnt/disks/persist