bigMapReduce.js is now hanging on several buildslaves:
http://buildbot.mongodb.org/builders/Linux%2064-bit%20DEBUG/builds/929/steps/test_11/logs/stdio
http://buildbot.mongodb.org/builders/OS%20X%2010.5%2064-bit%20DEBUG/builds/843/steps/test_11/logs/stdio
http://buildbot.mongodb.org/builders/OS%20X%2010.5%2032-bit/builds/3529/steps/test_9/logs/stdio