问题描述：在Xcode 5.1.1中用模拟器iOS 6.1跑Tests提示如下错误：
2014-06-18 14:40:49.581 sim[15948:303] /Applications/Xcode.app/Contents/Developer/Platforms/iPhoneSimulator.platform/usr/bin/sim: Dead bootstrap subset.
2014-06-18 14:40:50.817 sim[15948:303] Error spawning child process: No such file or directory
未找到方法，好歹只有测试跑在iOS6.1跑不了