pbench-trafficgen: capture trex yaml config file

- Includes unit test update

Author: k-rister

agent/bench-scripts/gold/pbench-trafficgen/test-22.txt

@@ -197,6 +197,7 @@ Iteration 3-revunidirectional-74B-1000flows-0.0pct_drop complete (3 of 0), with
 /var/tmp/pbench-test-bench/pbench/tools-default/sar
 /var/tmp/pbench-test-bench/pbench/trafficgen_test-22_1900.01.01T00.00.00
 /var/tmp/pbench-test-bench/pbench/trafficgen_test-22_1900.01.01T00.00.00/metadata.log
+/var/tmp/pbench-test-bench/pbench/trex_cfg.yaml
 --- pbench tree state
 +++ pbench.log file contents
 /var/tmp/pbench-test-bench/pbench/pbench.log:[debug][1900-01-01T00:00:00.000000] [pbench-trafficgen]processing options

agent/bench-scripts/pbench-trafficgen

@@ -846,6 +846,14 @@ mkdir -p $benchmark_run_dir/.running
 echo "$script_name $pbench_cmd" >$benchmark_run_dir/$script_name.cmd
 chmod +x $benchmark_run_dir/$script_name.cmd
 
+if [ "${postprocess_only}" == "n" ]; then
+	if [ $traffic_generator == "trex-txrx" -o $traffic_generator == "trex-txrx-profile" ]; then
+		if [ $skip_trex_server == "n" ]; then
+			cp ${pbench_tmp}/trex_cfg.yaml ${benchmark_run_dir}
+		fi
+	fi
+fi
+
 function record_default_iteration {
 	local count=$1
 	local direction=$2