Fix wrk2 on ubuntu1804.
Fix wrk2 on ubuntu1804.

PiperOrigin-RevId: 369983670

GoogleCloudPlatform/PerfKitBenchmarker,GoogleCloudPlatform/PerfKitBenchmarker,GoogleCloudPlatform/PerfKitBenchmarker,GoogleCloudPlatform/PerfKitBenchmarker