performance: remove tidb_enable_batch_dml (#19633)

tidb-performance-tuning-config.md

@@ -311,7 +311,6 @@ The following sections explain how to handle each of these cases. You need to ad
 If your workload involves frequent small transactions or queries that frequently request timestamps, [TSO (Timestamp Oracle)](/glossary.md#timestamp-oracle-tso) can become a performance bottleneck. To check if TSO wait time is impacting your system, check the [**Performance Overview > SQL Execute Time Overview**](/grafana-performance-overview-dashboard.md#sql-execute-time-overview) panel. If TSO wait time constitutes a large portion of your SQL execution time, consider the following optimizations:
 
 - Use low-precision TSO (enable [`tidb_low_resolution_tso`](/system-variables.md#tidb_low_resolution_tso)) for read operations that do not need strict consistency. For more information, see [Solution 1: use low-precision TSO](#solution-1-low-precision-tso).
-- Enable [`tidb_enable_batch_dml`](/system-variables.md#tidb_enable_batch_dml) to reduce TSO requests for batch operations
 - Combine small transactions into larger ones where possible. For more information, see [Solution 2: parallel mode for TSO requests](#solution-2-parallel-mode-for-tso-requests).
 
 #### Solution 1: low-precision TSO