benchmark/fs/write-stream-throughput.js can call bench.end() without calling bench.start()

[Trott]

• Version: 10.0.0-pre
• Platform: n/a
• Subsystem: benchmark, fs

In benchmark/fs/write-stream-throughput.js, it is possible (if dur is very short) that bench.end() gets called before bench.start(), and that will throw an error. Example at https://ci.nodejs.org/job/node-test-commit-aix/11455/nodes=aix61-ppc64/consoleText:

fs/write-stream-throughput.js
    /home/iojs/build/workspace/node-test-commit-aix/nodes/aix61-ppc64/benchmark/common.js:192
        throw new Error('called end without start');
        ^
    
    Error: called end without start
        at Benchmark.end (/home/iojs/build/workspace/node-test-commit-aix/nodes/aix61-ppc64/benchmark/common.js:192:11)
        at WriteStream.<anonymous> (/home/iojs/build/workspace/node-test-commit-aix/nodes/aix61-ppc64/benchmark/fs/write-stream-throughput.js:57:11)
        at WriteStream.emit (events.js:136:15)
        at finishMaybe (_stream_writable.js:633:14)
        at endWritable (_stream_writable.js:641:3)
        at WriteStream.Writable.end (_stream_writable.js:583:5)
        at Timeout._onTimeout (/home/iojs/build/workspace/node-test-commit-aix/nodes/aix61-ppc64/benchmark/fs/write-stream-throughput.js:46:7)
        at ontimeout (timers.js:454:11)
        at tryOnTimeout (timers.js:304:5)
        at Timer.listOnTimeout (timers.js:264:5)
    assert.js:43
      throw new errors.AssertionError(obj);
      ^