config txn-total-size-limit in tests (pingcap#848)

the latest tidb version has enlarge this and reject to start up if
txn-total-size-limit > 100 * (1<<20)

relate code:
295:	TxnTotalSizeLimit   uint64  `toml:"txn-total-size-limit" json:"txn-total-size-limit"`
724:		return fmt.Errorf("txn-total-size-limit should be less than %d with binlog enabled", 100<<20)
727:		return fmt.Errorf("txn-total-size-limit should be less than %d", 10<<30)

Author: july2993

tests/run.sh

@@ -32,10 +32,16 @@ stop_services() {
 }
 
 start_upstream_tidb() {
+    cat - > "$OUT_DIR/tidb-config.toml" <<EOF
+[performance]
+txn-total-size-limit = 104857599
+EOF
+
     port=${1-4000}
     echo "Starting TiDB at port: $port..."
     tidb-server \
         -P $port \
+        -config "$OUT_DIR/tidb-config.toml" \
         --store tikv \
         --path 127.0.0.1:2379 \
         --enable-binlog=true \